I've always struggled with this because up until I was like 23, my cousin cut my hair for free...thereafter, he charged me like $10 a pop since I was making money. Then since I moved out of my hometown years ago I've kind of had to fend for myself in figuring this out and I get conflicting theories.
When I briefly lived in Manchester NH, my haircuts were $12 so I generally gave like $15 or $16 total.
Now I'm back in Boston and my haircuts have been $18 pretty consistently. Now I would think that $22 or $23 total (nearly 28% tip) would be more than enough. But I have this asshole friend who's insistent that if you don't just leave $25 you're a "real dickhead" (exact words). Which to me is patently absurd. You're telling me I need to leave this motherfucker nearly 40% for taking 10 minutes to give me a high and tight?! Fuck outta here!
Now, generally I do just leave $25, especially if that's the exact change I have, cause I feel cheap asking for $2 back or whatever. But if I have 2 $20 bills, I'll ask for $17 back and won't feel at all bad about it. It's not like I'm getting hour long hairstyles and full head massages and shit.
What say you all? I could totally be in the wrong.