Actually, if the tires have been stored properly in 'still air' (no breezes), out of the sun, & at a stable temp between about 10 & 20-25° C, then anything up to about
5 (FIVE) YEARS old isn't really pushing it!! :lecturef_smilie:
It's only once you get the tires out of storage and into moving air, sunlight, and fairly significantly changing temps (especially if that occurs rapidly!) that they really start to 'age' &/or 'go off'.

In fact, there's quite a few very experienced & renowned 'tire guru's' out there selecting tires for things like World Class Race Teams, Fleet Managers, Transport Companies, Rally cars et al who
PREFER to use tires that've been 'aged' for a while - in some cases,
at least a year or more!! :shocked:
This is because the rapid 'evaporation' of the aromatics in 'fresh' or 'green' tires means that they will wear pretty damn quickly & possibly behave unpredictably until they've been put thru a few 'heat cycles', cycles that you may have little control over if they occur on the vehicle/road; while tires that are a year or so old have done all that during their 'aging' and they've done it in a relatively controlled manner! So mildly 'aged' tires tend to work better, last longer, and behave more predictably than 'green' tires fresh outto the manufacturing plant!! There's even people out there (running race teams & transport companies, fleet managers etc) who have been known to 'bake' their 'green' tires for a while in order to emulate a year or so of 'aging them properly' & in a controlled way before they even
think about using them on a vehicle! And from personal experience, I can tell you the difference between 'green' & 'baked' tires (for the better) is
really noticeable! nojoke
So don't be scared or even too wary of tires that have been stored in a (reputable company's) tire warehouse for as much as a few years, they might even work better & last longer for you than those 7 month old tires you would've otherwise rejected!!