All cakes must be quite cold before storing, otherwise there will be condensation inside a closed tin.
Put plain or frosted cake layers in a cake container with a cover. Or, invert a mixing bowl over the cake plate and your cake will keep fresh for days.
Fruit cake should be wrapped in greaseproof paper and a clean tea-towel or in cling film and stored in a cool place. Or, wrap in kitchen foil and replace in the baking tin.
Differences in keeping times depend on the type of cake: a fatless sponge will keep fresh for only 1–2 days, but one with added fat will keep for about 3 days. Creamed sandwich or layer cakes will keep for 1 week. Light fruit cakes keep for 2–3 weeks and rich fruit cakes will store well for at least a month.