I have planes that have been in the garage for 25 years, don't think its great for them. But I have not seen a problem, mine is a connected garage so it does not get as cold as the outdoors.
I do keep some in the basement, as many as I can get away with. She does catch on after awhile. If she has to move a plane to sit on the couch and watch tv there is a problem. Lol
like said, run the glow engines dry and add a few drops of oil, elect bring the lipo's in and put on storage charge.
great that you ask, I try and take care of mine also and this is the best place to get info.
Sticks