Unlike modern cushioned shoes, calluses both protect your feet and allow you to feel the ground you walk on.
I'm a podiatrist - here's what your feet say about your health
Corn and calluses - Stride Health
How to Treat a Corn or Callus (with Pictures) - wikiHow
2019 “What's New in Barefooting” archives
10 Ways to Dissolve (and Prevent) Dead Skin Buildup on Your Feet
Science - Page 227
Corn Treatment (What Causes Corns & How to Remove Them)
Why It's so Important to Take Care of Your Feet – DrScholls
Rejuvenate Your Feet with the Appropriate Care They Deserve — Callus Peel, by Beauty Heaven Therapist
Calluses: symptoms and removal - Salvequick
Embrace Your Ugly Feet
How to Get Rid of Calluses on Feet
Diabetes Foot Care: Tips and Importance