@Susan1404 The problem with that is that the amount of cleaning needed isn't really contingent on the length of stay, but on how clean or messy the guests are. There are guests who can totally trash out a place in one night and those who can stay for a month and leave it spotless.
I just have a private room/bathroom to clean and my cleaning routine is the same no matter how a guest leaves it, so I don't really care one way or the other, and while the majority of my guests leave it really neat and clean, I've had 3-nighters who left it far messier than other guests who stayed for 2 weeks.
I guess what you could do with longer stays is put in your listing info and message guests when they send an inquiry or request and you see that they have entered dates for longer than a week (or 2 weeks, whatever you want) that you do a quick half hour clean once a week for guests who book that long and charge XX amount for it. That would keep things from getting too bad in case the guests are slobs. And that it's not an option, it's the way you run your listing.
Perhaps other hosts will have some better suggestions.