@Sally190
I've had quite a few longer term guests and I have learnt to play it by ear a bit.
For guests staying over a week but less than a month, I offer them to clean their rooms and do a linen change half way through their stays. Some take me up on it and others not, e.g. my current 10 day guest said not to worry about it, but I did supply her with two sets each of bath and handtowels and washcloths when she arrived.
For guests staying a few months, I offer the same, but once every couple of weeks, but they never want it, so I supply them with two sets of bedding and towels each so they can do it themselves. Most don't want you messing around with their stuff or in their room too often.
However, I have had guests that do not keep the room clean nor take care of the linens. So, I leave make up wipes in the bedrooms, which have a sticker on them asking the guest to use these to remove make up instead of towels. I do this with short term guests too. It seems to have helped.
I also told my current long-term guest that although I knew she would keep the room clean, I would need to go in every couple of weeks to clean some stuff that even the cleanest guests never do, e.g. dust the bookshelves and shutters, vacuum the upholstery. She was happy to accept this as I'm sure she wasn't planning to do that level of cleaning!
As for use of the washing machine, I restrict this to guests staying over a week. Anyone else can pay me to do their laundry (£3 a load, which I think is very reasonable). I don't want loads of short-term guests messing with my machine and potentially breaking it, nor putting on a long wash for two t-shirts, as I have an 8kg machine. I have noticed that some hosts restrict guests to one load per week. I think that's a good idea and I might try it.