Is it true that foot orthotics really work?

Most of the time. . If you use them properly. If you're looking to beef up the shoes you already have, get a good insert or custom orthotic: you can use them to improve the shoes you already own. Over the counter orthotics typically break down over 6-12 months, but a good custom orthotic will last years. This will also ensure it is customized exactly to you and will correct your foot specifically.
Yes. I have prescribed orthotics in various forms to many patients over the years with excellent results.
Orthotics. Yes . As with dr beresh , I have prescribed them for many years with excellent results .
Yes. If they are made correctly for the right diagnosis and reason.