Foot orthotics or supports are made to improve biomechanical abnormalities of the feet and to help the biomechanics of the foot. There are several various kinds of foot orthotics and methods of making them for podiatrists to use and select from. Many people require and do benefit from custom made foot orthoses while some might be helped by the simpler and cheaper mass-produced foot supports. Which one is best for each individual will depend on precisely what is causing the problems and just what the treating clinician suggests is the best for that individual. All different foot orthotics have got unique design features and a good doctor will attempt and match those up to the requirements of the individual. If that is not done the right way, then there might not be any improvement in the symptoms.
Foot orthoses are not without their issues. If they are not the correct one for the individual, chances are they won't help. You are also limited by what shoes you need to use, in that you need to be able to fit them into the shoe and there may not be sufficient space. There are also kinds of footwear, for example the flip flops which they just can not be used in. This tends to present a challenge in warmer climates that make closed in footwear meant for foot orthoses uncomfortable. There are alternatives, for instance, the Archies that have a foot support integrated. The design of the arch supports in these sandals are similar to what you should get in an over-the-counter arch support, but probably not as good as what you will get from a custom made foot orthotic. Using these do give a helpful replacement for foot supports, based on where you can wear them and the nature of the biomechanical problem. If you do need foot supports there is no harm in trying these types of choices or raising it with your treating clinician to determine what they think.