A feature many people forget when shopping for point of sale software is the loans function. This function is mostly used for more expensive items, which the customer is allowed to take home for some days to try out. Or in fashion, when your customers are shopping for their busy husbands, and want to try these trousers at home.
The loans function allows you to register each loan and have a up-to date inventory of each item that a customer has at home. When the customer returns the item, you can either invoice it when the customer liked the item or put it back in stock when it was not what they were looking for.
A very simple feature, which might make your life a lot easier.