Is it ok to wear previously gently worn shoes of someone else. if the new owner of the shoes wears orthotics for overpronation and bunions?

It's not suggested: Although one can control the instability of the foot and ankle with a custom orthotic, even a gently worn shoe may have been compromised by the instability of the previous owner. All shoes should pass a brief test. 1. The counter of the shoe should be stable. 2. The break in the shoe must be at the first metatarsal joint and 3. It should not be able to "dish rag" in the center if the shoe.

Shoes: No, because of your need for orthotics you cannot use another person shoes.

Ok yes, recommended?: Not a fan of wearing someone else's shoes! if they show no distinct wear pattern and they are disinfected wearing them with your orthotics should not affect their function nor have a negative impact on your feet. This of course assumes that the shoes are appropriate for your foot type and won't infect you with any fungal, bacterial or viral diseases.