How often should car tires be changed or have air put in?
 

How often should car tires be changed or have air put in, if usage is for a sedan or wagon and someone that works 9-5 5 days a week (15 miles each time)or less than that, if it really makes a difference.

Depends on road conditions and driving habits to determine tire wear. Tread wear (deepness of the groves), outer tread rounding or scalloping are all determining factors. Time is not always a factor unless the tires age and have sidewall cracking before they actually have excess tread wear. As far as "airing" is concerned.. Pressure should be checked on a monthly basis if not sooner! Always keep an eye on tires for going flat and even then, just don't air it up and leave it at that! Have it checked out for a leak or puncture. Hope this helps ya..

Thanks for useful advice

As a rule of thumb, tires will lose/gain 1 psi for every 10 degrees of temp change. If you set the tire to 32psi when it is 70 degrees, the tire will read around 30psi at 50 degrees.

Rotate the tires every 7,000 - 10,000 miles will keep the tire wear even. Tire rotation is typically cross to the drive wheels; that is, on a RWD left front goes to right rear, right rear goes to right front, etc. For FWD left rear goes to right front, right front goes to right rear, etc. Of course, if you have unidirectional tires or different sizes on front/rear, this dos not apply.

"Double X" pattern?
 

Interesting. What I didn't realize is that there is some judgement made by the mechanic as to the best pattern to use when rotating tires. This article on Columbiana CDJR's site describes a "Double X" pattern for AWD and 4WD vehicles. That patern seems to make sense to me.