hello @Lizet3
Welcome to CC
It's reasonable to expect bed linen to be changed at least once around every 7 days.
Do your Guests have access to a washing machine?
If so there's no reason they can't wash them themselves, is there?
In regards to towels, it's always good to provide 2 per person so they have one to dry their hair.
It all depends I guess how eco friendly your accommodation is & the type of Guest as to how many towels and how often they are changed or how many you provide.
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All the best & happy hosting