Just knowing your accurate size is not enough for properly fitting your feet, since shoe companies often have different size standards for each measurement. For example, Hoka One One fits long and a little wide, Solomon fit long and narrow, while La Sportiva fits narrow and short. Brooks usually fits true to size, Saucony is often wide, Asics can be narrow as is Nike. However, almost all brands have one or two shoe makes that do not follow this rule, so always try on a shoe before you buy it.
Trail vs. Road
The two major variations in shoes are road and trail. In these subgroups shoes diverge into varying levels of stiffness, aggressiveness, tread, durability, and flexibility.
FEATURES OF A ROAD SHOE
Road shoes are going to be more flexible, lighter, more cushioned and have a softer tread. Because a shoe manufacturer assumes that a road will not vary much, they create a corrective shoe that helps an athlete avoid over-pronation or supination. Wearing a road shoe on the trail will leave your foot unprotected, not to mention you will absolutely destroy the soft tread on your shoe as you slip and slide your way down.
FEATURES OF A TRAIL SHOE
Unlike the road, trails are completely variable. If you are running rockier, more technical trails, you might want a stiffer shoe with a rock plate and ample toe protection. If you are scrambling, you might want a stickier tread, if you are running muddy, wet, or snowy trails, a shoe with a more aggressive tread might serve you best. Due to the more unforgiving nature of a trail shoe, wearing them on the road will impose greater impact on your foot. The asphalt will also tear apart the tread.
IS THERE AN ALL-IN-ONE SHOE?
No…but there are some solutions to running on mixed terrain. Shoes like the Salomon X-Mission and the Brooks Caldera are more flexible and light in terms of trail shoes with a less aggressive tread. They are perfect for running to trailheads or on long runs that might involve both bike paths and trail. However, they are going to have less protection and durability on the trails and will grow uncomfortable if worn for a long period of time on the roads. They will also wear out faster than the average shoe as they are not designed specifically for either terrain. If financially reasonable, it is best to invest in both a pair of road shoes and a pair of trail shoes.