Are your feet perfect? Probably not. Most people overpronate at least slightly. As many as 10% of people experience pain from plantar fasciitis. And who hasn't had a blister on their foot before? The good news is that solving these common ailments is usually as simple as adding the correct replacement insoles to your favorite pair of shoes.

Runners, doctors, therapists and shoe salesman often talk about overpronation. Most people know the condition by other names such as "flat feet" or "fallen arches". Overpronation is a very common problem. You might not be born with flat feet, but flat feet become more likely as your body ages. Causes include weight gain, hormonal changes during pregnancy, or even long hours spent on hard surfaces. What exactly is overpronation? It's the failure of your arch to properly support your foot. As you put weight on your arch, it collapses, causing your foot to "overpronate," or roll inward more than it should. Overpronation puts added stress on every part of the foot and leg. Left untreated, overpronation can lead to serious pain and injuries including Achilles tendinitis, inflamed knee tissue and plantar fasciitis.

Fortunately, most overpronation can be easily and instantly corrected with "orthotic" (bracing) insoles. Motion control and arch support insoles are both effective in treating overpronation. As the name suggests, arch support insoles feature maximum bracing, with a molded-in arch of durable, tech-grade graphite or plastic. Motion control insoles also feature superior arch bracing along with a deep heel cup to prevent rolling ankles and provide maximum heel stability.

If you're experiencing heel pain, it's most likely plantar fasciitis. Although you feel the pain in your heel, the problem is actually due to an inflammation (fasciitis) of the connective tissue that stretches from your heel to the base of your toes. Normally, this tissue acts like a bow-string, to keep your foot's arch properly flexed. However, irritation can make the plantar tissue too painful to stand on. Plantar fasciitis can feel like a bruise on the heel, as if you have stepped on a stone. Others describe the pain as "heel spurs." (FYI: While spurs -- calcium deposits -- can occur, they usually don't cause pain.)

Many things can lead to plantar fasciitis: old injuries, arch supports that are too high or too low, working on hard floors, even being overweight. If you suffer from plantar fasciitis, try any insole with a built-in arch. Arch support insoles can significantly reduce the pain. Rest, ice, massage and losing weight are commonly recommended as well as being sure that you thoroughly stretch your feet and calves before you exercise.

The number one cause of blisters is something engineers call "shear." You would probably call it friction. Friction causes heat, and heat raises blisters. Blisters are not just a painful nuisance; They can alter your running and walking form and lead to other problems in your hips and legs.

Many inserts have been designed to protect your feet against blisters. Some insole models use a top layer of anti-friction fabric, laboratory-designed to wick away moisture, a leading cause of friction. Other insoles incorporate a top layer of memory foam (or polyethylene), that molds itself to the base of your foot, virtually eliminating any chance of shear.

Now when it comes to the question "how often should I replace my insoles?" the answer may surprise you. If you walk, run or exercise daily, you might consider replacing your insoles every three to six months. This is because with heavy use, the foam cushioning in any insole tends to "bottom out" or flatten. The tiny air cells in the polyurethane cushioning eventually collapse in spots, compromising your comfort.

Also, when you do replace the insert that came with your shoe, it is important that you remove the old pair as opposed to doubling the inserts up on top of each other. Not doing so can cause your shoes to fit improperly or cause your new insoles to not work as effectively.

If you are seeking a remedy to any of these common foot ailments, give specialized replacement insoles a try and keep your feet healthy and comfortable in every athletic shoe you wear.