I know of two cases with modern laminated bows that were left strung for a very long period that took some set. One was a Bear Super Kodiak that still had the original string on it, probably left strung for 15 years, another was a Stottler flat limb longbow, I believe that one while being strung for years, also caught some serious heating in a closed vehicle. Do not leave thick cored longbows strung for unnecessary long periods.

 

Never had a problem with keeping my laminated limbs strung for a year or more. Of course they were kept in human heat conditions and stored horizontal on a wall.