It takes a long time to wear out a Birkenstock, a favorite sandal of Boomers (with or without socks). Here's a comparison of a new pair to an old pair worn daily
10 Ways To Care For Your Birkenstocks - The Restory
How to Add New Holes to Birkenstock Sandal Straps - iFixit Repair Guide
Fitting Your New Birkenstocks To Your Feet: 101 – Happy Feet Plus – Footwear For a Healthier You