OK, my feet are practically flat, (even low arches are too high for me.) So solid plastic insoles were out of the question unless i wanted to pay 200 bucks to have some fitted. Gel insoles have worked for me every time. The BEST are the full-foot liquid gel kind, (as opposed to the solid gel or heel/instep kind) But all gel types are better for flat feet. They allow equal distribution of weight as would occur with flat feet. They also allow you to walk in a way that would help you develop arces (forming the foot so the gel forms in the middle.