No brainer, I'm running an ROI of around 10-1. I hear comments like "I love those cards" and "keep sending them". I cleaned a sofa and bedroom of a six month reminder last yesterday. She told me she has been thinking of getting the sofa cleaned but pulled the trigger when my "Time for a touch up" card came. You can't even begin to calculate the potential money it will help generate when your client actually remembers your name and refers you to someone. It works great for me because I'm too lazy to send out reminders on my own.