Collecting vintage frames taught me that sizing standards have changed over the decades. What worked in the 1980s doesn't always translate to modern measurements.
I measure vintage frames carefully before buying. The numbers on the temple might not reflect current size due to material changes over decades.
I verify actual measurements against marked sizes. Acetate frames can shrink over time. Metal frames are more stable but hinges may be worn.
Beautiful vintage frames that actually fit, because I verified measurements rather than trusting old markings.