It takes a long time to adjust to FOs the first time you own them. Also what they are made of makes a big difference and varies from person to person. The QUALITY of FOs can vary a lot too. I've been a lab rat for the UW orthotics students for several years now and have gotten to try just about every material available to make FOs, and see a wide range of methods/approaches. These students are very close to graduation, so it's close to what they will be making in practice.