Depends on your relationship with this customer, and whether you think this is going to be a habit. Personally, I don't charge for little things like that, especially if I've done a large job for them in the past. If they are going to be PitA customers, then send them a bill.

Now, if you choose NOT to bill them, then you need to do this:

Send them an invoice with the service call discounted/credited to $0.00. This allows you to DOCUMENT the times you've been there GRATIS, so if there ever IS an issue, you can pull those invoices and say "Look, Mr. Customer, I came here no charge on date A, B, C, D, E... and didn't charge you a dime. You are being billed for this call because...." Works like a charm, and the customer understands that you are doing them a favor, and not just hooking them up. Once they realize there are hard costs (truck roll, your time, etc), and that you've eaten it, they become less likely to call you at home, in fear that the next time, that discount may not be there...

Just my $.02 worth

Fred Forlano
Higher Definition