You know....this thread pops up every so often and the responses are usually similar, and I've never really chimed in even though I have a wee bit of a different opinion. So just this once I'll throw in my .02psi.
I agree with pretty much all that was said here, with the exception of a few places in the Caribbean, most notably here in Curacao where I live. You can make a living being a scuba instructor. I know literally dozens of people that do it. I'm not talking about people living out of back packs and combing beach sand. I'm talking about people that own cars, and houses and heck some even have kids in private schools! Do they live high on the hog? Heck no, but they live a what would be in the US a lower middle class lifestyle.
Here's the thing, the scuba industry down here, is an actual industry. There are a few operators that have multiple locations that do a few million a year in sales. Those kinds of places need, and can afford a little more upper class instructor. Sure the rubber meets the road with the young DM who is taking a break before finishing university and needs enough money for bus fair, a studio apartment and a decent sized beer budget, an even bigger beer budget if he can live at home...
Sure it helps if you can speak multiple languages, have sales skills, fix a compressor or drive a boat, but more importantly are you willing to learn those skills. Are you the type of employee that will study Rosetta Stone on your lunchbreak, come in on your day off and learn how to swap out a third stage head, and pony up on some Sudafed for an unscheduled night dive (your 5th dive of the day) because someone called in sick. There are orginizations all over where if you are this type of employee you will find yourself moving up the ranks. People always talk about the owners of boats and dive shops making the big bucks. Well a lot of them came from doing just this. You move from DM to OWSI, you get sales bonuses, you pick up extra shifts, then you learn to drive a boat and get a bonus for that...next thing you know the dive shop is opening up a new location and that location needs a manager...boom there you go.
Now, here is the caveat. We all like to think we are that person, but let's face it, most of us aren't...I know I'm not! We're talking about the kind of employee that starts as a bank teller and 4 years later they are a branch manager, they start as a bagger at a grocery and wind up running the store in the next town over. They start as a waitress at Applebees and down the road they are doing regional sales training. You can do that in the dive industry as well, in the right place, under the right circumstances, and with a wee bit of luck added to your perseverance. Although here is the trick, if you are that person, the world has a lot more opportunities where the risk vs reward is so much greater than a ho hum existence as a dive instructor. It has to be a labor of love, because for all that hard work can you make a living...sure I see it every day, but is it the best living you make?