How much do I tip people working on my house?

I recently purchased a new home in Cobble Hill and have a few folks working on the house. Is there a general rule of thumb on how much one is supposed to tip (if at all) for any of the following:

- Contractor
- Painter
- Plumber
- Electrician
- Cleaning Service

Please forgive my ignorance – any help would be appreciated.

Thanks,
Clueless in Crooklyn

By nohazmats | 12/16/2007 8:01 PM