Baseball

Topps has printed baseball for seventy years, so the year on the back matters most.

The same player turns up in a set at the same number across decades of reprints.

The year is often only on the back, and the copyright line there is the most reliable year on the card.

A front-only scan of a vintage Topps card is the most common way to end up in the wrong year.

A rookie card carries a big premium, and buyers search for it by name. Check the flag before you list.