BrickUnderground

I tend to tip every time my building people (renting here) do anything for us, except certain things that the building requires. So I tip on Christmas, and then I wind up giving something every time they show up to change lightbulbs, remove air conditioners, etc. The only time I don't is when it's plumbing or something the building requires, like when we all got new doors. Am I going too far? Should my Christmas tip cover almost everything? I'm fairly generous, I think, at holiday time. Not the most generous, but not the least, by any means.