You should be comfortable in a cave by yourself and you should know what kind of a diver you are. Are you aggressive or more conservative when you are alone? Does your trim suffer if no one is watching? Have you got the presence of mind to fix problems that arise? Can you plan a dive and execute it without someone watching over you? Have you got cave awareness or will you get lost as soon as your eye drifts away from the line?
The main argument to support the theory that buddy diving is superior to solo diving is that ‘two brains are better than one.’ No matter how much redundant equipment you have, the theory goes, at the end of the day you only have one brain so it is nice to have a backup. This theory suggests that somehow two people working together to solve a problem will mean that it is more likely to be resolved, for example two people lost in a cave are more likely to get out after communicating about their predicament.
I would argue that it is precisely this redundant brain that is likely to be the source of potential problems to begin with. You can control a lot about your diving; you can control yourself, your gear, your route and how far inside a cave you will venture. Yet you cannot control what goes on in your buddies brain. What another person is thinking or feeling at any one time is often a mystery. Are they pushing themselves to be there? Are they happy and focused on the dive or have they had a bad day at work and they’re feeling suicidal or homicidal for that matter? Humans in general aren’t exactly real good at communicating. Our two lost mates from the example above probably got themselves in the ‘crap! where’s the exit?!’ predicament because of a lack of communication in the first place... ‘I thought you were keeping track of where we are?’ ‘No, I thought you were - you where the one leading!’ Surely the double fatalities that occur would prove that a redundant brain can’t solve all problems.
There are times when solo diving in my opinion is clearly a good option, in tight silty passages for example, a buddy would hinder rather than help. Doing it solo is often more effective, but of course, just like with the real S word, it can be more fun with a buddy. If you can find a buddy who has a similar breathing rate, a similar pace, similar goals and interests inside the caves and they have as much interest in your satisfaction and pleasure as their own, then you are indeed more likely to have more fun and a good time. Yet anyone can tell you that finding a perfect match is no easy feat.