I stick pretty close to 20% for my hair and the occasional massage i get.
For cheap services like nails at my vietnamese salon, I tip a lot more. Like if it's $43 for mani/pedi, i'll pay $60. I've read the nytimes articles.... they need the money a lot more than i do at this point.
By the same token, i also tip $5 to the hair wash girl at my salon (in addition to the 20% i gave to my colorist and stylist on their services).
When i was in my 20s and early 30s and cash was tighter, i was tighter about tips. And honestly i think totally within my rights. $2 for the shampoo girl. $5 for mani/pedi. And 20% elsewhere. Not offensive, but not over the top. But we have a lot of cash now, and i use these services so infrequently, that i'd rather tip generously for the cheap services since they need it more than me. It probably only adds up to an additional $80 throughout the whole year. No matter how much cash i have though, i think it's ridiculous to start tipping 25% on the higher earners. When i go in for cut and color, it's $300. I'm not tipping $75. It's ridiculous i'm even tipping $60. (And as an aside, the colorist tipping is most ridiculous of all, given that between consult, bleach application, mixing color, and applying, i think they only spend 25 minutes on me, and they're able to work with multiple other clients while i'm there.)