"T.I.P." means To Insure Promptness. Originally for delivery boys, now commonly used the same as gratuity (a money gift for a service). I'm not a big "tipper". Probably due to my time at regionals making little money- not that I have a lot now! I've never tipped a maid, nor have I ever met one. They clean after I'm gone, so I never think of them. The driver gets one Dollar/Euro/Pound/etc- or just a dollar if I don't have their money. The crew passes an envelope on the bus and all 8 to 10 of us put about a dollar in, so the driver gets a nice big tip in an envelope.

I also tip the bartender, waiter, etc. What percent? That's another topic. Especially if you add different countries and customs.