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
Birkenstock Arizona Ancient Mosaic Taupe Sandale 36-42 Fußbett normal & schmal | eBay
Birkenstock sandals ARIZONA SCHMAL MAROON
Birkenstock mules SCHMAL MADRID BIG BUCKLE GRACEFUL TAUPE