A good thing to do is bring a sleep sheet which basically a bed sheet sew along the side and bottowm, basically a very light sleeping bag.  Its good to have because you never know the condition or cleanliness of teh bed you’ll be sleeping in.  Also, bring your own pillow case.  

If you’re worried about the bedding, a light sleep sheet and pillow case are fine. Some places are strict and won’t let you use your own bedding (to prevent transfer of bedbugs). It’s a good rule.

I dont get it why are sleeping bags not ok? will they not let you use them at hostels? i was planing to also bring a sleeping sheet but i dont think that will be warm enough?

Bed bugs like to live in fluffy stuff like the filling of sleeping bags.  They hitch a ride to the next hostel in your sleeping bag and getting rid of an infestation is a nightmare for the hostel.

aurora, Hostels are justifiably concerned regarding the prospect of insect infestation carried inadvertantly in lodgers’ sleeping bags. I’ve personally been in a situation where the entire dormitory was quickly affected, the residents itchily afflicted – thank goodness management immediately fumigated resolving the issue. No, a sleep sheet will indeed not be warm enough, but most hostels provide minimally a blanket or duvet.