Originally posted by Aqua Buoy
Are you being specific to Thailand??? If you are there isn't much help I can give you.
Yet, as an Instructor, your possiblities are endless. If you choose to remain an Open Water Scuba Instructor (PADI OWSI or equivalent), then you may be limiting yourself. The lifestyle is different yes, so is the money. You make a sacrifice from this point of view, but the work is very rewarding.
Continuing education! You can move up the ranks, and not only on the PADI or Rec ladder. Do some tek, if it tickles your fancy, teach it someday perhaps. Join up on a EMC course, Dive Chamber technician, perhaps even start your own company.
In the end, wherever you are, you have to have the ambition. If you're happy with just being an OWSI (or equivalent) then that is fine. If not, find new things to learn, get more qualifications and make yourself more marketable. Make contacts. That way you can go as far as you like!!!
If you doing an instructor course for collecting a 'badge' then the certifying agency will be more than happy to take your money, but it won't be much use to you if you don't want it.
Sorry if I have no info Thailand specficially, hope the rest helps.
Peace
=-)