The foot is a complex area of the body since there are numerous small bones that are joined together by a lot of ligaments and controlled by so many muscles. On top of that we bear the bodyweight on the feet and subject it to so many pressures. To make it worse we place the foot inside the artificial environment of footwear. It's because of this that the career of podiatric medicine exists because there is just so much that will go wrong with the feet and associated structures. Podiatric physicians utilize a lots of different interventions to manage problems of the foot and lower limb.
Foot orthotics can be used to take care of the wide array of problems that may go wrong with the feet. The aim of foot supports are to change alignment of the feet in the direction of a more corrected normal position or to lessen the stress in structures of the foot that are producing symptoms so that they can improve. The foot supports do this via having various design characteristics that are designed to match the foot. A custom made foot orthoses can do that. However, over the counter orthoses can do this, usually by chance. They might or might not match the foot of the person using them whereas a tailor made one will. There are various characteristics that could be varied, like the height of the mid-foot along with the amount of cushioning. There are even designs referred to as the Kinetic wedge and Cluffy Wedge.
At times the cheaper over-the-counter type supports are better and other times the bespoke ones are better. It will all rely on the type of the problem, the foot type and shape as well as the advice of a good clinician in regards to what is the best alternative. If you have a problem with your feet and think you need some foot orthoses, then see a good podiatrist.