If you have hard water, you may wind up getting calcium and lime buildup. However, it's easy to clean with CLR and a toothpick. If they start to act funky or spray weird or not spray at all, then put some CLR in the bottom with some hot water. Let it sit for about 10 minutes, then drain the tub, then turn the water and jets back on and they should work well again. The ones that don't just poke with a toothpick or a stick pin and the calcium will come right out. You can do the same thing with shower heads.

My Bain Ultra Air tub will be a year old in Dec. My water is neither hard or soft. I've not had any problems with build up of dirty, discolored or clogged holes. 10 minutes after the pump goes off, a 90 second air "purge" starts that blows out any water that might be in the air chambers. I've read about this sort of thing with water jetted tubs and is one of the reasons I chose air.
Monica