i'd like to add to this great post:
For AWD owners:
-it is important that you ROTATE your tires frequently, front-to-back only ALWAYS keeping your tires on the same side of the vehicle.
-keep the same air pressure, all around.
-if you replace a tire, unless they are within 5000mi or km, you will be running a larger diameter on the new tire. best to find a used one with similar tread depth or youll have to buy a whole set of 4
Why don't I want to rotate side to side?
Wear patterns are different front to back. If you start swapping side to side, then the same tire will be on the back for 2 cycles and another will be on the front for 2 cycles.
This will cause the wear to happen unevenly between the front and back. This will cause one (or 2) tires to become a different "size" or circumference and will make the diffs and Transfer case work harder, or even overheat/burn out. An under inflated tire can do the same.
I did learn a good way to adjust and check this if you want to really get "detail oriented" or OCD.
find a very flat stretch of road. Do this where there is no one around as you will be stopping a lot.
With all the tires inflated to just above where you are planning to run them,
mark all four of your wheels with tape or chalk. I usually aim this straight down (closest to the ground)
Then pull forward several yards keeping the van as straight as possible. If you can stick your head out and watch the wheels, go about 15-20 revolutions
Inch yourself forward so that the wheel you can see is back to straight down.
Then set the parking brake and take a walk around the van. If all the wheels have the marking straight down like before you are good to go.
If one or more of the wheels did not make it to straight down or over shot being straight down, then you will need to adjust the pressure in the tires to change their diameter slightly.
Less air means the tire will get smaller, causing it to go around further to travel in order to travel the same distance or it would overshoot your reference wheel.
more air would be the opposite. Let a little bit of air out of the tires that came up short of straight down and try again.
It doesn't take much to do change this so do one tire at a time, and in very small increments.