@Melanie982
It's a tricky one. I host long term stays, but I am a homeshare host so my set up is very different from yours.
I think you have to decide if your price justifies leaving certain supplies (toilet paper, laundry detergent, toiletries etc.) as a starter kit, or enough for the whole stay. Whichever you decide upon, do be sure to make it crystal clear to set expectations. You can always add more (underpromise, overdeliver).
Also, are you providing cleaning during the stay, or do you expect the guests to clean up after themselves while there? This is an important thing to consider for long term stays. Again, set expectations. If you are cleaning for them, how often and what does this involve? Is your cleaning fee (if you charge one and, if not, your accommodation rate) sufficient to cover this expense? If you expect them to clean themselves, make sure you provide enough equipment and products to do so and make it clear in a house manual etc. where to find them. The same goes for laundry of bedlinen, towels etc.
At the end of the day, it totally depends on whether you want to make sure the guests have enough to get started or your prices justify providing enough products to see them through the whole stay.
If you are really after a good review, special touches can make a difference. One of the things my guests love the most is a personalised 'welcome' board (blackboard etc.) with their names on it. You might include a welcome basket (search here on the CC as there are lots of suggestions). I also include little letter holders with leaflets, such as maps, tourist information, local restaurant/take away menus, that sort of thing.
One crucial thing is to regularly check up on the guests to make sure they have everything they need (use your own judgement as to how much or how little contact they prefer), but also know your limits. Don't give in to every little whim/demand of the guest if you feel they are asking for too much. You don't have to provide anything that is not stated on the listing/communicated to them.