What exactly you leave with a customer can make a big difference in customer retention rates.
I have been thinking lately that just a business card and a receipt is not enough.
A spotter bottle is a good idea, but like business cards, I don't think they contain enough information.
I have been considering small custom pocket folders to leave with the customer.
They are the perfect size to not easily loose track of, and can be neatly tucked away somewhere by the customer for future reference.
As well as your contact info, coupons and list of services, using them to note the original service date and price, 6-month date and a 6-month recurring discount, and the 1-year date and 1-year discount will give more reason to keep it.
I think noting the dates will go a long way towards countering the tendency of the majority of customers to underestimate when you were there last, and to be able to know exactly how long they have to take advantage of discounts, which should create some incentive.
A sprayer bottle or business card just can't accomplish that.