2bird, with modern materials that is no longer true. Self bows are another matter altogether. All wood bows (or bamboo) should not be strung unless they are in use. Fiberglass-backed (or equivalent) can be left strung indefinitely. The bow I'm shooting this season was my cousin's, one I got for him years ago, and after he passed away the bow was forgotten in a closet for several years. When his son found it and gave it to me, the FF string that was on it had stretched completely out. The bow was undamaged.