I tip the Barber every visit. Bring a jar of nuts. If you don't tip, then figure what you spend during the year and add10-15%. Lunch guys, well they are salaried guys but perhaps the Jar of nuts also.
I suppose you can also figure what you spend and give them %. They are not "servers" so its not like tipping a wait staff. Maybe 5%?
Im suprised OBM (Orange blobman) didn't say " I don't tip, they tip me"!