Do you create campaigns to suit the player-characters? When the PCs reach a stopping point, do you move on from that world and create a new campaign?
Or do you create worlds that your PCs happen to adventure in?
Obviously, our games are never as cut-and-dried as this, but think about your general approach. In practice, does your campaign world exist separate from the PCs?
This difference in approach highlights a key distinction between old-school and modern play approaches.
Modern games create heroic characters who are the focus of big stories. The game is all about the characters.
Old-school games were set in a big world where characters lived and died. Blackmoor and Greyhawk existed regardless of who was playing it. The characters accomplished great deeds within those worlds, and gameplay focused on their heroics. But the world continued on.
Both approaches are useful. Just beware of getting stuck in one.