Not everyone has the same feet. In fact, no one has the same feet, so technically speaking, there is no reason why everyone should wear the same insoles in their boots. There are people with very high arches, medium arches, low arches, sensitive heels, hammer toes, misshapen feet, webbed toes and flat feet and there are custom insole options available for exactly those kinds of people. Or for people who just want a little bit of added comfort in their boots to cut back on strain and fatigue.

Your feet serve an important purpose in training and combat. They allow you to walk, run, crawl, and are involved in almost every physical activity you participate in. If a soldier is not performing at the highest level, there is always the possibility of further injury for that person or for someone else in their company. For this reason, it is very important to ensure that the combat boots are properly fitted and comfortable for the wearer.

Think of your feet are a complex mechanical device with many individual parts that work together to perform a unique function. Depending on your genetics and physiology, your feet may have less than ideal characteristics for what it is designed to do. For example, if you have low arches, your feet are more likely to cramp during physical activity and hinder your performance. Using an insole that provides additional support in the arch could fix this problem .Custom insoles supplement the shortcomings of your feet Insoles can be fitted to the exact specifications of the wearer. If there is a low arch, or flat feet and the arch support is too high, the same difficulty can occur and the wearer will not perform to the best of their abilities.

In some instances, there may be a person who has a misshapen foot due to a prior injury or a birth defect which, under normal conditions, may not be a hindrance but under the stress and strain of a combat situation, or other extremely physical situation, it may cause a problem if it is not properly supported and cared for. For example, if the deformity of the foot causes blisters on the feet, that will cause the person to perform more slowly than usual. Likewise, if there is a noticeable lack of support on the foot more serious damage can occur such as nerve damage or broken bones. This is especially true of someone with webbed toes or hammer toes, as they have less control over how their toes move within the boots.

Of course, not everyone has some kind of outstanding issue with their feet. Some people may just be uncomfortable with the level of cushion and support that comes stock in their combat boots. It is imperative, when wearing combat boots, that the wearer is comfortable for long periods of time. Standard issue insoles may not provide enough padding, which can cause unnecessary strain on the feet and cause fatigue. There are options for these less specific foot needs as well, so there is never any need for a person to be uncomfortable in their combat boots.

Other Resources:
Blisters - http://www.thefreedictionary.com/blister
Hot Spots - http://www.drfoot.co.uk/phpBB2/post-4949.html
http://www.superfeet.com/