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
Sizing
Birkenstock Arizona Big Buckle Slide Sandal (Women) | Nordstrom
Amazon.com | Birkenstock Unisex Arizona Brown Sandals - 8-8.5 B(M) US Women | Sandals
Womens Birkenstock Arizona Sandal - Brown | Journeys
Birkenstock Air Cushion Full-Length Insoles – The Insole Store