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
The secret of Birkenstock's enduring success | CNN
Birkenstock Women's Arizona Almond Big Buckle – Orleans Shoe Co.
Arizona Birkibuc Stone | BIRKENSTOCK
Birkenstock Arizona EXQ LE Exquisite | FIRMAMENT - Berlin Renaissance
A 630 Polyurethane Blue | BIRKENSTOCK
Birkenstock Arizona Birkibuc Sandal in Stone Grey – V&A Bootery INC