Much of what people go to "professionals" for is very do-able at home. Nail salons, eyebrow plucking kiosks, and similar services come to mind. Yes, there are some extreme high-maintenance things that should require training, but as a society we're leading our young people to believe it's biologically impossible to apply nail polish or wield a pair of tweezers on oneself.
Exactly this! I think it should be a requirement that you should at least attempt this kind of stuff on your own before paying for it. Yeah, that does mean you might wind up with a bad self dye job, or an uneven haircut, or messy nail polish or whatnot. Maybe you'll even fail: my first attempt at plucking my own eyebrows was, shall we say, a learning experience.
I don't think it matters, really, after that if you pay for someone else to do it for you or not. (Well, as long as you can afford it without being stupid and going into debt because you must get your nails maincured every week or whatever.)
But it gives you a lot more appreciation for someone doing the task WELL if you know you've struggled with it. It drives me nuts to see women berating the people who do their nails and hair for missing one small little spot - like, really, lady, could you have managed it that well? Have you ever even tried this before?
I get a haircut once a year or so (hair is long and straight, not much else to do to it), and I get my toenails done maybe every other year as a treat. My eyebrows are another story; they want me to come in every four weeks, but I have them do it nice once and then maintain them myself for as long as I can before going back in to do it again. But knowing how badly I fail at doing them completely myself makes it a lot easier to hand over the $25 to have someone else do them a few times a year, and makes me a lot more forgiving if I notice she missed a strand here or there.