How Many Summer Car Seat Covers Do I Need for Summer?

I only had 2 baby car seat covers last winter. I realized that I was always short on clean ones so I’ve decided to buy more baby car seat covers for summer. I think 4 additional covers will do. I’m looking for covers that will dry easily and are dirt resistant. It’s such a hassle to wash them everyday, especially when you only have a couple of them. I guess it would be wise to have extra baby car seat covers handy for those days the baby decides to make a big mess in his car seat. An infant car seat cover is meant to keep the baby’s seat clean anyway.