How long do cakes last (after being decorated/frosted)
If my husband is home, cake lasts roughly and hour and a half :)
If it's real buttercream made with butter/egg, keep it in the fridge with a slice of bread covering the cut sides to prevent the cake from drying out. Should keep for several days to a week depending on how moist the cake is.
If it's shortening based frosting, you can keep it at room temp under a cake dome for a couple of days.