Whats your opinion on this? I have been leaving an invoice after each cut with their current balance they are going to owe at the end of the month. For example, if I cut the lawn twice I would write their name at the top of the invoice, the date cut, what I did (lawn service), what the price per cut is (say its $40), then I write "Due at end of month ... $80". I keep a continuing tab going on so next week I would write $120 for the "due at end of month" section. I use the note card size invoices you can buy at Walgreens. It takes me 1-2 minutes to write these per lawn. What do you think? Am I just wasting my time?