I don't charge a cleaning fee- I think it depends on a few factors. If a host is just renting out a room in their home to one person or a couple, which is my situation, I just factor it in to my booking fee. Also I have a 3 night minimum stay, and most of my guests stay for at least a week, maximum 2 weeks, so it's not like I'm having to turn it around quickly and clean daily for 1 nighters.
If I had a self-contained unit for larger groups, I might charge a separate cleaning fee. It would be more palatable, I think, for a group to split that charge. Some groups may leave it really clean and tidy, some may leave a big mess, it'll average out.
I've also read here that many guests consider that if they are charged a separate cleaning fee, that is license to leave the place a mess, so there's that to consider as well.