I will put some oil on the fire.
The problem with the ow cert and also aow is that they state you are allowed to go to 40m, but not trained for. And here the big big problem starts with divecenters. They don't think you can do the training on your own. In every sport you can do and progress as an autodidact, but not in diving. Every step needs to be taken by hand.
There is no way to show or proof with a sort of exam or competition results you know what you are doing like in other sports, but you always need to do the whole course. If you don't do and just pay for a card, the instructor is not following standards and this can give a problem if something happens (which can always be the case, even with a completely right planned dive).
If you have never been deeper than 27m, the step to 40m is a lot. If you are unsure, do a course.
If you are an autodidact, you can read the theory, do some calculations about the gas consumption and then progress slowly with a buddy, 30m first then then 32, etc. But the problem still can be in future that a divecenter requires a cert.
If you think you are unsure, please do a course.
Maybe there is no deeper lake or divesite near your home, but a lot of divers never learn to dive without a guide (this is in my opinion really bad, even the fresh open water diver must be able to dive on his own with a buddy in easy circumstances. In my country all divers dive without a guide after open water cert, but abroad, you see that even if you have 3000 dives that they expect that you need a guide).
And diving without a guide and able to dive on your own is important in my opinion about the advice on taking yes or no extra courses. So if my prejudice says not dived a lot on unguided dives, the course for sure is a good idea.
If you wrote that you had been several times to 35m on your own with a buddy, I would probably look different about the question. It proves you are less unsure. (No, I don't think every diver that dives outside a theoretically certification limit is a dare devil as some instructors state. I have seen enough that this is for sure in most times not the truth. It shows the problem with self training/autodidactically training and slow clubs/people that try to slow a diver down which is diving more than average, so can progress faster than average).
And again: self training or being an autodidact is not for everybody. There also will be divers that go to too soon too fast too deep. But I think a course will not stop them. But as soon as you are a little bit unsure, do a course. Diving is not dangerous, but the environment can be dangerous and the deeper you come, the longer the way back to the surface, the risks are higher on deeper dives. And it is not only the longer way back to surface, also shorter NDL, narcoses, etc.
If you are or are not insuranced if you dive outside a certification limit depends on the insurance and the country you live. In my country a cert is not needed, everybody is insuranced even if you do stupid things. Abroad it is the travel insurance which sometimes talk about certs, most times also not. So you have to read the rule about your insurance.
So, the conclusion would be: a lot of divecenters will require it if you want to dive over 30m with them. It has to do with liability. There is still no option to do self training or being an autodidact in diving. Self training is not for everybody, you know if it can be something for you. If you are unsure, the course is not a bad idea. If you are worried about insurance issues, read your insurance.
I agree that there need to be standards for instructors when teaching courses. But I was also a diver that has done all kind of dives outside a theoretically certification limit and got pointing fingers etc about my 'misbehaviour'. But it wasn't. I am in a lot of sports an autodidact, but could not be this in diving. Maybe the group that really can act as an autodidact in diving is not that big, but it is the same as highly intelligent people, they also need a way to improve and to learn. On schools there is more and more possible for children that learn easier and faster than others. In diving it is 1 standard. And yes, I agree, it is sometimes a quite low standard and sometimes trying to bring divers further too fast.
I have never seen a diver that could do an advanced nitrox course with only 30 dives (that is the minimum amount in standards).
I have seen only 1 time a diver that could do an intro to cave course after 50 dives (but only in wetsuit, in drysuit the bouyancy was too much bouncing).
So here standards can be more strict. But remember selling courses is also a commercial thing and improves income for divecenters/instructors. This means a course cannot take a week as it becomes too expensive and too long for the 'always in hurry traveler', so there is found a way to make money, don't get a lot of accidents and fun for the customer.
From what I see now, some or quite a lot of divers need more dives to become a safe diver than just 4 in open water. This has nothing to do with being a bad instructor, but some divers are completely NO naturals under water. I know divers that have 60 dives and still sometimes pop up for some meters as they really don't feel how bouyancy works. Such divers are a pain in the ass for divecenters and instructors as diving is most times a fixed price. So this means in commercial divecenters that a lot of divers get a cert while they are not completely ready for it. Some divers need 2 dives more, but some need 10 or 15 more. And 1 or 2 maybe can be arranged, but more will bring too much extra costs for the divecenter. Not passing students means unhappy customers, but passing students means they still need supervision on next dives. So this is why guided dives are widely required (sadly).
On the other hand, you will have divers that are naturals and do all the skills in 10 minutes and have a natural feeling for bouyancy. Also these divers need to get experience, so the ow course with 4 dives is not bad. Then they can progress directly to aow and then probably need some dives for experience. But they can go faster than average. And if you try to slow them down, they will do things on their own.
Every diver is human. Humans make mistakes, but also every diver learns different. Agencies made programs for the average diver, which works well for them. But if you are not an average diver, it will bring annoyance and did not get the best out of you as a diver if the instructor just follows the curriculum. You get passed and get the cert, but are not able to dive with a buddy without a guide.
So it is hard to say to you, do the deep diver course, or don't. There are several reasons to do it, and the most important is that divecenters can ask for the cert. If you want to learn from it, try to find an instructor that follows the standards, but also understands that every diver is human and that everybody is different. What works for you won't work for everybody and vica versa.
And remember, there is training made because there was a need for it. So you can use it if you think you can learn from it. But the first person who did things, there was no training. Training comes as people ask for it. I am diving a sidemount ccr and bought it to use as bo ccr. Have done several dives with 2 ccr's, so find out the autididactical way how to use it. Now there is a course for it. No, I don't feel any need to do the course as I already know how it works. But it took me some time to learn and with a course it was a shorter path for sure. I also explain others how I do it, so with explaining is how teaching starts. Then someone writes an official course and then the commercial part of diving comes to pick it up.
I think we we would take fresh open water divers to 35m we would have more panic attacks for sure. So I am not against courses. But I also know that not everybody will have profit from a course and only brings in money.
Good luck with your choice.
The problem with the ow cert and also aow is that they state you are allowed to go to 40m, but not trained for. And here the big big problem starts with divecenters. They don't think you can do the training on your own. In every sport you can do and progress as an autodidact, but not in diving. Every step needs to be taken by hand.
There is no way to show or proof with a sort of exam or competition results you know what you are doing like in other sports, but you always need to do the whole course. If you don't do and just pay for a card, the instructor is not following standards and this can give a problem if something happens (which can always be the case, even with a completely right planned dive).
If you have never been deeper than 27m, the step to 40m is a lot. If you are unsure, do a course.
If you are an autodidact, you can read the theory, do some calculations about the gas consumption and then progress slowly with a buddy, 30m first then then 32, etc. But the problem still can be in future that a divecenter requires a cert.
If you think you are unsure, please do a course.
Maybe there is no deeper lake or divesite near your home, but a lot of divers never learn to dive without a guide (this is in my opinion really bad, even the fresh open water diver must be able to dive on his own with a buddy in easy circumstances. In my country all divers dive without a guide after open water cert, but abroad, you see that even if you have 3000 dives that they expect that you need a guide).
And diving without a guide and able to dive on your own is important in my opinion about the advice on taking yes or no extra courses. So if my prejudice says not dived a lot on unguided dives, the course for sure is a good idea.
If you wrote that you had been several times to 35m on your own with a buddy, I would probably look different about the question. It proves you are less unsure. (No, I don't think every diver that dives outside a theoretically certification limit is a dare devil as some instructors state. I have seen enough that this is for sure in most times not the truth. It shows the problem with self training/autodidactically training and slow clubs/people that try to slow a diver down which is diving more than average, so can progress faster than average).
And again: self training or being an autodidact is not for everybody. There also will be divers that go to too soon too fast too deep. But I think a course will not stop them. But as soon as you are a little bit unsure, do a course. Diving is not dangerous, but the environment can be dangerous and the deeper you come, the longer the way back to the surface, the risks are higher on deeper dives. And it is not only the longer way back to surface, also shorter NDL, narcoses, etc.
If you are or are not insuranced if you dive outside a certification limit depends on the insurance and the country you live. In my country a cert is not needed, everybody is insuranced even if you do stupid things. Abroad it is the travel insurance which sometimes talk about certs, most times also not. So you have to read the rule about your insurance.
So, the conclusion would be: a lot of divecenters will require it if you want to dive over 30m with them. It has to do with liability. There is still no option to do self training or being an autodidact in diving. Self training is not for everybody, you know if it can be something for you. If you are unsure, the course is not a bad idea. If you are worried about insurance issues, read your insurance.
I agree that there need to be standards for instructors when teaching courses. But I was also a diver that has done all kind of dives outside a theoretically certification limit and got pointing fingers etc about my 'misbehaviour'. But it wasn't. I am in a lot of sports an autodidact, but could not be this in diving. Maybe the group that really can act as an autodidact in diving is not that big, but it is the same as highly intelligent people, they also need a way to improve and to learn. On schools there is more and more possible for children that learn easier and faster than others. In diving it is 1 standard. And yes, I agree, it is sometimes a quite low standard and sometimes trying to bring divers further too fast.
I have never seen a diver that could do an advanced nitrox course with only 30 dives (that is the minimum amount in standards).
I have seen only 1 time a diver that could do an intro to cave course after 50 dives (but only in wetsuit, in drysuit the bouyancy was too much bouncing).
So here standards can be more strict. But remember selling courses is also a commercial thing and improves income for divecenters/instructors. This means a course cannot take a week as it becomes too expensive and too long for the 'always in hurry traveler', so there is found a way to make money, don't get a lot of accidents and fun for the customer.
From what I see now, some or quite a lot of divers need more dives to become a safe diver than just 4 in open water. This has nothing to do with being a bad instructor, but some divers are completely NO naturals under water. I know divers that have 60 dives and still sometimes pop up for some meters as they really don't feel how bouyancy works. Such divers are a pain in the ass for divecenters and instructors as diving is most times a fixed price. So this means in commercial divecenters that a lot of divers get a cert while they are not completely ready for it. Some divers need 2 dives more, but some need 10 or 15 more. And 1 or 2 maybe can be arranged, but more will bring too much extra costs for the divecenter. Not passing students means unhappy customers, but passing students means they still need supervision on next dives. So this is why guided dives are widely required (sadly).
On the other hand, you will have divers that are naturals and do all the skills in 10 minutes and have a natural feeling for bouyancy. Also these divers need to get experience, so the ow course with 4 dives is not bad. Then they can progress directly to aow and then probably need some dives for experience. But they can go faster than average. And if you try to slow them down, they will do things on their own.
Every diver is human. Humans make mistakes, but also every diver learns different. Agencies made programs for the average diver, which works well for them. But if you are not an average diver, it will bring annoyance and did not get the best out of you as a diver if the instructor just follows the curriculum. You get passed and get the cert, but are not able to dive with a buddy without a guide.
So it is hard to say to you, do the deep diver course, or don't. There are several reasons to do it, and the most important is that divecenters can ask for the cert. If you want to learn from it, try to find an instructor that follows the standards, but also understands that every diver is human and that everybody is different. What works for you won't work for everybody and vica versa.
And remember, there is training made because there was a need for it. So you can use it if you think you can learn from it. But the first person who did things, there was no training. Training comes as people ask for it. I am diving a sidemount ccr and bought it to use as bo ccr. Have done several dives with 2 ccr's, so find out the autididactical way how to use it. Now there is a course for it. No, I don't feel any need to do the course as I already know how it works. But it took me some time to learn and with a course it was a shorter path for sure. I also explain others how I do it, so with explaining is how teaching starts. Then someone writes an official course and then the commercial part of diving comes to pick it up.
I think we we would take fresh open water divers to 35m we would have more panic attacks for sure. So I am not against courses. But I also know that not everybody will have profit from a course and only brings in money.
Good luck with your choice.
