Maybe I’m an , but the little girl pees as soon as her diaper comes off. This led to me washing our changing table pad covers constantly. So I started “barriers of defense” and started layering waterproof sheet savers over waterproof lap pads. That way, when she inevitably pees during a change, I can whisk away the dirtied pad or sheet saver and not have to launder and change the entire pad cover.
If you choose to use the waterproof sheet savers you really only need 1 fitted crib sheet and 2 to 4 waterproof sheet savers. The fitted crib sheet should require few changes since the waterproof sheet savers on top will keep it dry. You do, however, want to get multiple waterproof sheet savers since you will need to change those regularly.