I remember back in the 70s-80s, Master Charge and Visa credit card numbers were shorter – 13 digits instead of 16 digits as they are today. I think the used to be in a 4–3-3–3 pattern.

Somewhere along the way they were all converted to what we have today. Do you know when?

Do you think we’ll ever go from 16 to 18 or even 20? Will they ever run out of numbers?