The nearest place that sells tires, Walmart, is seven miles from my house. I wouldn't let them touch my Chevy Cobalt.

I like owning and using tools. The rate-of-return on tools is huge.

I've turned tire maintenance into one of my "efficiency" or "outcome manipulation" games. Through a process I call "tire whispering," I'll get at least 60k miles out of the original tires on Frau Putzer's X3. I got 40k miles out of the high-performance tires on my 535i. My top five mileage records for a set of four tires are: 79k, 74k, 70k, 70k, and 68k miles. But, those were wearing them down to 2/32". I'm more risk averse in my old age. So, now I replace tires when they've worn down to 3/32".

The X3's tires might age out (six years of being installed) before the tread's down to 3/32". That's our primary vehicle since it gets the best MPG (better than the Chevy Cobalt), the new car warranty will expire due to time before due to mileage, and it has tires that might age out before being worn out.

The Cobalt got rear ended years ago. The insurance adjuster had a checklist for determining the value of the car. One of them was tire tread depths. Near the end of the tires' life, the depths of all the circumferential channels on all four tires were well within 1/32" of each other. The adjuster said "I've never seen that before."