I always set the customer up with their own account, that they are responsible for paying for. I might lose $10/month, but I save at least that much in my time

I always set the customer up with their own account, that they are responsible for paying for. I might lose $10/month, but I save at least that much in my time worrying about collecting, plus it reduces my responsibilities. Mosso (Rackspace Cloud now) has a nifty little feature that lets you setup clients on your account and set the rate they are billed at etc. Mosso worries about getting the money, you just sit back and profit. They even have a support service you can pay for (I think its $5/mo/domain), and throw all of your customers at. They will relay the information to you, and answer any questions about downtime that has to do with Rackspace etc, all while acting like they work for you.