One of the most important things that can be done to extend tire life is proper and frequent rotation. Tires that wear evenly will perform better and help keep noise at a minimum as the tire ages.
This chart will be adequate for most vehicles on the road.
There are, of course, a few exceptions. Performance tires and performance vehicles may or may not always allow for rotation.
Front and rear tires different sizes?
Recommended intervals for rotation are about 3,000-5,000 miles. More frequent rotation is important early in the tire's life as a new tire will wear more rapidly than one that has been in service for several years. I recommend staying closer to the 3,000 range for the first 10-15k and aiming towards the 5,000 mile range from that point on. Frequent rotation will help ensure you get the most out of your tires and help protect your investment. Read more tire tech info.