I used to leave stamped, addressed envelopes, but now i know it's a waste. i just leave a little card through the door. It has taken time and some "customer training", but now almost all my customers send me a cheque. The database I've made for my work, Round Organiser, has a search function to find customers, not only based on a surname search but also amount, house number , and road, makes finding them easier and quicker.