Bath towels here only get used once before washing, but the one hanging in the bathroom to dry hands on gets washed once a week or so. We've got a closet full of bath towels so no worries about using them more than once. At school I probably go two weeks or so before washing mine. I've got two though so it takes a month before I wash them. Same idea- I'm clean when they are used.

Dish towels get used way too much before getting washed. I always get a new one out when I need it because I know they often fall on the floor and get kicked around before somebody picks it up and puts it back on the towel bar.

Sheets/bedding, gosh, my mom does them maybe 2-4 times a year. At school I do them once a month because I have fleece sheets and they get flattened out and don't feel soft anymore. I often spray them with fabric refresher several times between washings.