I am a 20% tipper for everything unless the service was horrid and then I might leave 10%.
Service people earn tips and deserve tips for good service. Tips make up a good part of their wages.
My poodle is at the goormer less than an hour as well but that does not mean the groomer does not deserve a tip. I am thankful that my dog is not caged all day waiting to be groomed and then placed back in a cage with a huge dryer blowing at him until I al "allowed" to come get him at 4.
If someone can't tip everytime, then it would be nice to do something special over the holidays, like freshly baked cookies, bread or something just to say thanks.
Go cheap = you get cheap