I have three
By the way, this topic is me trying to get out of doing laundry by talking about it instead, which definitely equally productive.
I live alone and have 6. Let me explain.
I have 3 personally. Two normal baskets for whites and colours, and then another bigger one for towels, dressing gowns, oven mitts etc.
I get my bedsheets washed by a laundry service. I have three baskets that they own. Generally I only use one or two, but I use the third if I need extra sheets washed.
It costs me 10 a month to get 2-3 sets of sheets washed. I am more than happy to pay a tenner to not have to fuck around with 3 sets of bedsheets.