When making a custom cake that requires carving the layers, freeze them first.
Wrap them well in plastic wrap and put them in the freezer until they're frozen solid. Cake layers are much easier to carve when frozen. Plus, freezing shrinks the crumb, so your cake doesn't crumble when you slice it up and serve it to your guests.
No, freezing the layers in this manner does not dry out your cake if you wrap it well. You get a dried-out cake when the grocery store bakery freezes cakes already decorated.
Just don't leave the layers in your freezer for months on end and then expect them to still be good. I'd say two weeks, at most. Usually, I bake and freeze the day before I decorate.