What do you think about finders fees, when should you pay a finders fee and how much should be paid.

Lets use a sub contractor as an example:

You are too busy so you pass on work to a sub contractor, should they pay you a small fee for passing on the work?

How much should they pay and should you get a percentage of the work they get from that customer?

Maybe not such a bad idea to create some form of contract wit the sub contractor to prevent them from taking over the customer.
I have learnt from experience that it doesnt take long, never more than 2 years to get the customer back again. The upside to getting the customer back is that they get to see how bad the service is from contractors, so when you inform them about your "new rate" it doesn't seem so high.