It's actually depends on many factor and where you park most of the time,
easy example :
A daily drive car parked outside all the time within 2 years rubber compound get harden grip won't be great especially wet surface even there's 5mm of tread, if you have to travel far with harden rubber tyre you always have to check for hairline cracks at sidewall to be caution blowout at highway speed.

Meanwhile a shaded parking car without being moist and direct sunlight, will last 5-6 years until the rubber compound get harden, but will also bare a cost of balancing more frequent because long park create high pressure point and the donuts were not circle like daily drive tyre.

The most important thing is to take care your air pressure at least once a month by following placard (usually recommend inflate when tyre is cool).
An optimal inflate tyre will reduce the unwanted wear not just tread but the most important part is protecting sidewall from blowout which is way horrible every driver to be experience.