Here's another big one. If you decide to take your little teardrop south for the winter and you end up driving on our salty roadways, wash it off before you store it. Salt is deadly on any surface, including aluminum if left over the wintertime. It will pit the aluminum. It can be polished back to a new look again, but it is a lot of unnecessary elbow grease, when all you needed to do in the first place was wash off the salt after a long road trip.
This question should be answered based on where you decide to store your trailer during the winter months. If it's stored in a damp environment, then yes definitely remove it. If it is in a heated garage, there is no need to worry about it. Everyone has a different place they keep their teardrop stored. I leave my mattress inside the trailer all year round. However, My teardrop is stored inside my shop and the shop is temperature controlled all season. When in doubt, pull it out :-)