@Jules106 Reasons not to allow pre-viewings:
Security risk. These are complete strangers. You really have no idea what their intentions are.
Hosts who've done this say it was a waste of their time- guests never went on to book,
Guests may use this as an opportunity to try to pressure you to book off-platform.
Reasons not to take long-term bookings:
Guests staying over 30 days may fall under landlord/tenant laws and if they won't leave after their time is up you may have a hard time getting them out.(I realize some hosts live where there are restrictions on shorter bookings, though)
If the guest is objectionable in some way, you'll have to put up with them for a long time.
I agree with @Alon1's suggestion- a one night booking so they can check out if they like it, and you can get a sense if you want to host them that long. If I did this, and I thought "No way", I'd probably offer them a refund of the one night, minus my expenses, including my time, since they wouldn't have booked it for one night if they didn't think it was a prelude to a long-term booking.