In your opinion, what is the best way to to bill your clients? Last year I told a majority of my clients to just leave a check under the mat (after every cut) or hand it to me in person. This year I am trying to take a more proffesional, effecient way of billing. I was thinking about sending my clients an invoice (either mailed, or emailed to the customer) at the end of every month. If they didnt pay by the 14th of the next month I would tack on a late fee. Do you guys think this is a good idea, or what is the best method of going about it?