For example: if booked for three hours and already collected gift, and a gentleman decides he has somewhere to be earlier than expected. Is it considerate to return what isn't used? Or would that be on him? I have never really had this happen often but it did a couple of weeks ago and I genuinely could not think of what the proper etiquette would be for this situation. Of course the person didn't ask for a gift return and was great and respectful but I just wondered for future reference what would you guys do? The only reason I would say it would be on him is because of bringing the subject up would be taking about donation which I would rather not. Any inputs?
Did he give you notice? As a client, I say if you blocked that time off for him and he had to change unexpectedly, I wouldn't see any reason at all to refund him. If he gave you plenty of notice and you wanted to do so just to be nice, go ahead. You could always give him a little discount on a future session as well if you wanted to.
No it was a spontaneous decision. I think a discount would be fair for sure. Thank you 
yes it depends it is up to you sh-t happens but it would like returning a gift to a store with a receipt you would get a in store credit how much also be up to you [ kinda like good for business] my be a very good review but this only my 2 cents
What would the store give you then?
No need to cite Nordstroms return policy, but if you took something back to Macy's and said, "hi! I wore this once.. I planned to wear it to my sisters wedding, but she broke up with her fiancé." They will look at you like you're nuts. Lol.
Great input
If you rented a car for 24 hours but brought it back after only 4, we both know you would pay for the entire 24 hours. You are a very kind and considerate person for even asking. Yet we both know, what goes around, comes around.
Good karma for you!
If it was completely unexpected YES I would have offered to refund some of his donation
but if he had already said this was likely to happen then no.