Exactly. If you're going to do a birthday-based PIN, it's important to consider that the 10s digit of month and year have heavily reduced search-space. 4-digi

Exactly. If you're going to do a birthday-based PIN, it's important to consider that the 10s digit of month and year have heavily reduced search-space. 4-digit Birthday-pins are probably good as long as they're not your birthday or that of your kids, and you do the last 2 digits of year, last digit of month, last digit of day, go capture as much of the entropy from the date as possible.