If you order multiple drinks and the bar's packed: 20%+
"Depends on how much they order throughout the night. If it's four people deep at the bar and they come up and order three to five drinks for their friends every so often, then that's time I could be serving other people. And by that time, they ask me my name and shout my name across the bar and expect special treatment. If I'm holding a tab for them and keeping track of all that, then a bigger tip helps. At a busy nightclub, even if it's super busy, $1 a drink. At the craft cocktail bar where I used to work, we'd get super busy and I'd have two six-tops to myself and a whole bunch of people at the bar, and sometimes I'd get swamped, and 20% would be great."
If you're with a huge group: Auto-gratuity and another 10% on top
"The place I used to bartend, we'd take six to eight tops on our own. I'd have to make eight drinks that took me two to three minutes each, and take care of people at the bar. After a while, some people drink faster, so you get stuck with a single drink order. I'll ask 'Does anyone want anything?' Everyone stares at you. When you go back to the one person who ordered and drop the drink off, then everyone asks. Every time you go back to the table, people order another drink. If I do all this legwork and have to deal with stupid people for an hour or two and you tip me 10%, I'm gonna stab somebody. Some auto-gratuities are 18%, so even with that, it's not up to standard. Some people see auto-gratuity on their bill and say, 'They didn't ask me.' A lot of times you gauge out a table. If people are cool and appreciative, then there's no point. Sometimes it pays off and sometimes it backfires."
If you want to be a regular the staff likes: 50% on the total
"I think most regulars, most people who are liked at a bar have established themselves as being good tippers. A lot of bars have regulars that take up a barstool all goddamn day and barely tip. The ones you like are conscious of that. Instead of them sitting there for four hours, we could've had six to eight people sit at that barstool and make money on the collective checks. A lot of times people become regulars because they're nice to talk to, and they also establish themselves from tipping well. We had a regular [at the craft cocktail bar] who'd be there for three to four hours, and he'd read in the corner or he'd want to have an existential conversation. No matter what he had, he'd tip a $100. We'd usually hook him up with a drink or two, or buy him and his date a drink. No matter what, he'd tip well."