Although at this point in my life I don't have much in the way of extra stuff. I do keep a couple of onesies and sleepers for visitors to wear if they don't have their own, but those are special and kept to be used specifically as guest clothing.

I also keep a selection of various size diapers.

I've done this in the past. Usually with with clothing that doesn't fit me right. I'll have a little visiting, and the clothing fits them just fine, so when it's time for them to leave I make sure they take it with them.