I have a peg rack in the bedroom where all of my bows, both recurves and longbows hang strung year round. If they have lost any poundage it is so small it doesn't matter aand if it is a laminated limb, you can unstring it for a few days and it will usually come back.

I used to make strings for 3 different bowyers and they all said the same thing. Leave 'em strung, just not in heat or direct sunlight.