Contractors are usually paid either on an hourly or daily basis. Unlike others working in the service industry, plumbers don't rely on tips as their primary source of income. There is no obligation to tip, and the decision is entirely up to you.

Do you tip a drain cleaner?

Tipping a house cleaner who's employed not by you but by a cleaning service is optional. If you feel so inclined, 10 to 15 percent is acceptable. At holiday time, or if you're particularly impressed by a job (the gunk was cleaned from all your liquid soap dispensers), increase it, but by no more than $20.

What services should you tip for?