I think that it goes without saying that you should always, always have a set of clean sheets on hand for your child's bed. Same goes for pajamas.
But, I have a bad habit of leaving the clean laundry in the basement, near the laundry room. This is a habit that I will now break, at least for the sheets.
Let me tell you that, when your child wakes you up at a ridiculous time in the middle of the night because they have been sick in their bed, the last thing you want to do is trudge downstairs to get clean sheets. If I had just put them away, they would have been in the closet of his room and my only trip downstairs would have been to rinse out the gross sheets, which was bad enough.
I will also let you in on a little-known fact. If your spouse is out of town, that is the night that your child will throw up in bed. Or the power will go out. Or the basement will flood. You get the picture. Now go wash your sheets and put them in your kid's room.