If you do not know what type of motion your feet have and do not have the opportunity to have your foot motion evaluated by another person, use the following information to estimate your foot motion.
The best indirect measure of foot motion is the wear of the midsole, which is indicated by creasing in the midsole EVA foam. Note that a shoe with a polyurethane midsole will not show creasing. Fortunately, most running shoes are made with EVA foam midsoles. As a midsole breaks down creases will develop. A greater number of stacked creases or deeper creases indicate greater wear. Old shoes will display creases without applying a load while shoes with less mileage will need to be compressed with your hands. A neutral foot-strike will create creasing in the lateral heel of the midsole and medial forefoot of the midsole. Excessive creasing of the midsole in the lateral midfoot suggests that supination is occurring. Excessive creasing in any part of the medial side of the midsole from the heel to just before the forefoot suggests that the foot is experiencing over-pronation.
A fair measure of foot motion is outsole wear. The pattern of wear on the outsole may represent how forces are distributed along the shoe during stance. Compare the wear pattern from your shoe with the images below.
A wet footprint test is a common method for determining foot motion. Get your feet wet and stand on a flat surface that will allow your footprint to be shown. A paper towel works well. Compare your footprint to the images below.
One problem with the footprint test is that it is a static measure and feet have dynamic movements during stance while running. To make the footprint test better, compare seated (non weight-bearing) footprints with standing (weight-bearing) footprints. If the standing footprint has a greater surface area than the seated footprint then you probably need some pronation control. Another problem with the footprint test is that some people have footprints that match the above images but their feet do not move in the indicated way.
Although the relationship does not always hold true, there is a tendency for foot motion to be associated with arch height. Generally, the higher the arch the less the foot will pronate and the lower the arch the more the foot will pronate. Either stand on a hard surface and view the medial side of your foot in a mirror or take a picture of your foot and compare it to the images below.
Arch height works best as an indicator of foot motion for people at the extremes. However, there are people with high arches that over-pronate and people with no arches that supinate.