I freeze mine - my hubby's b-day cake is in the freezer as we speak. I won't have time to do it for this weekend so I baked and frosted it last weekend. I will take it out on Friday and let the kids decorate it after I've left it on the counter to defrost and let the condensation evaporate (maybe 5 hours).
One problem you may encounter is bleeding icing.
My freezer doesn't have any smelly foods in it that could be picked up in the icing like garlic.
The longest I would keep it in is a week if I was going to sell it. I wouldn't decorate it until after because of the bleeding.
I've done it for person use a lot and they are fine.
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