The Book of Knights and Ladies lists several cultures that do not have knighthood at various time. Which, if any would normally have a squire? Would esquires past the age of 21 have squires?

In those days apprenticing was fairly common, so it would not seem odd for a cavalryman to have an apprentice. He would not be called squire as such I think, but it could.

Esquires are still squires themselves and servants to their own lord/ knight. I do not think they would have squires themselves. It could however that the knight has an extra squire. Esquires are after all just squires who could not become knights themselves.

The Book of Knights and Ladies lists several cultures that do not have knighthood at various time. Which, if any would normally have a squire?

I usually play it that none do.
As Cornelius said, they might have a servant (called something other than squire)
But if they have a squire, they will cost the same as knights


Would esquires past the age of 21 have squires?

No, not squires
servants? If they could afford them, probably6 so as a mark of status