I do a bunch of sleeping on my sofa and I cover it with a freshly cleaned (plain, light, earthtone, sheet like) comforter once a week...on Saturday.

Actually it looks very nice...not bed like. I have several, as they are not the thick expensive kind and they start to wear after several washings.

Works for me, but, then, I'm alone now.. DH would not have gone for it..LOL!!