There are also bad suppliers who don't do their leg work. I've "fired" some companies who did great work for me because they couldn't be bothered to send a bill - I know I owe someone some money, but I don't know how much as despite begging they won't tell me how much or where to send it (I only have a phone number) - this bill could get larger, and they can come after me at any time for it...

Please don't be them. If you do good work make sure that you get your bills sent on time.