The tyres WILL "rot out", whether the vehicle is in use or not.
Well, not "rot"; (synthetic) rubber doesn't really do that, AIUI. It's more like drying out. And UV radiation from the sun.
The manufacturers' recommended usage period is something like three or four years, I think, and max age (including storage-before-usage, that is) somewhere around five or six.
That's the manufacturers' recommendations, and they of course have all the incentive in the world to keep those low so they can sell you new tyres every fifteen minutes. But still, I'd prefer to use tyres that haven't been used for more than about five years and aren't older than, say, max ten.
The manufacturers' recommended usage period is something like three or four years, I think, and max age (including storage-before-usage, that is) somewhere around five or six.
That's the manufacturers' recommendations, and they of course have all the incentive in the world to keep those low so they can sell you new tyres every fifteen minutes. But still, I'd prefer to use tyres that haven't been used for more than about five years and aren't older than, say, max ten.