I make this clear in my house rules, that for stays over 10 days we will add a mandatory mid-stay clean and charge them for it
Usually they don't want it, and most times I don't force it unless I have doubts about how they are using the apartment. But putting that in the house rules makes it so I don't have to provide for free.
If the reservation was a good price, I will provide a change of sheets for free left in the closet. If they got a heavily discounted stay, I do make them pay for the service.
I have professional cleaners it costs me over 100 for cleaning and linens, if my guest is paying less than 100 a night with a long stay discount I find it unreasonable to have to pay for this additional service myself.
For stays over 2 weeks, I impose the mid stay clean to avoid surprises at the end of the stay. Are they smoking inside, are the airing the apartment out regularly for example after cooking garlic or fish, etc.