I'm renting a garage, was hell to find one wide enough to be able to open the doors! In,any case the car will not age too rapidly that way
I spent 4 quid on some foam pipe lagging and some No More Nails, best money I've ever spent! Cut the lagging in half, then stuck bits on the wall all over the area where the edge of the doors are likely to touch (or frequently touch as is actually the case, my garage is barely wide enough).