Some lunchtime reading. Orthotics. They seem to work for some, but nobody can say why and what type will work for a given problem. In short, the case is far from proven.
http://www.nytimes.com/2011/01/18/health/nutrition...
Money quote: "Arches are an evolutionary remnant, needed by primates that gripped trees with their feet. Since we don’t do that anymore, we don’t really need an arch. Why would we? For landing — no need. For the stance phase — no need. For the takeoff phase — no need. Thus a flat foot is not something that is bad per se.” Flat footers: relax.
Balogna and I have been orthotics free for a year now and all seems fine. Certainly the shoes are a lot lighter without all that gunk in 'em.