I’ve never heard of artists charging by the hour before, and now it’s been mentioned twice in the same (short) thread … is this more common than I realize? All of my work was charged based on the work itself – as far as I know, anyway. (My most recent $120 tattoo only took about 1/2 hour; I doubt that she charges $240/hr and didn’t tell me!)
I’ve tipped on three of my four tattoos, all done by the same guy at the same shop. I tip $20-$30 on tats that were all between $50-$80, but likely would have cost more if I weren’t a repeat customer. So, it’s all factored in.
It’s usually the difference between a small tattoo that’s going to take a half hour, or an hour or two at most–those are usually quoted at a flat rate. Typically, large pieces that take multiple sessions to complete are charged by the hour. Sometimes they’ll estimate the time frame at the start of the project and quote you a flat rate based on hour and difficulty of execution. At least, this is how I understand it, this being my first personal foray into a large tattoo.