I have taken a few breaks from climbing here and there, sometimes for a few months at a time, and each time my shoes felt more like plastic than I remembered. It's not to the point where it's a whole new break-in process, but, it usually takes about a session or two to get used to them again. It's really about getting my feet used to climbing shoes again, the shoes usually keep the shape they had before I took my break, it's my feet that need to re-adapt to the tightness of the shoes.