I don't have a commission from you, but I will bring up a point you probably won't like. The Comissioner has fufilled their obligation by paying you up front. Why should they have to absorb the paypal fees for you not performing the work? I think you should refund the whole amount. Also if you haven't been keeping them waiting for months and months, paypal lets you refund the whole amount, and the paypal fees to boot, without costing you anything too.

Oh yes. If possible, I'll always try to incur as little fees as possible. As to why the commissioner absorbs the fees, it's because I WOULD perform the work, but if they think I'm taking too long, or have second thoughts, their financial situation change or whatever might come up, then I'll expect them to pay the fees.

However, if I'M the one canceling the commission (for whatever reason), then naturally, I'll refund the full amount.

Oh Yes, I'll agree if they are cancelling because their financial sitaution has changed, then no problem, certainly keep the fees. If they are cancelling because your taking too long, that's because the artist hasn't delivered the goods, in which case the blame falls back on the artist in that situation and the artist shoudl eat the fees. For example if you order a diamond ring from the store and it takes a long time and they keep giving excuses, no matter what when it comes down to asking for your money back the store cannot keep any amount of the money, unless they can proove that they have provided at least some product/services. In which case, a partial refund can be issued, but i've seen again and again where if you can't proove that you've provided the customer with somthing, they they get all their money back. If you can proove you've provided them with some amount of service (a preliminary sketch etc) then they get only partial refund.

Yeah, but unless we have agreed on a deadline, "too long" is only an opinion. "Too long" could be anything from a day to 2 weeks to a year. So unless we have set a deadline, you cannot really talk about taking too long.