As the hinges wear the door becomes harder to open due to striker alignment to the sagging door. That additional effort required by the handle wears it and the zinc alloy will eventually fail. The stiff wire link from the interior lever to the lock has a bend in it that gets straightened by greater than normal effort to open the lock. That makes the open point for that lever beyond its movement range.

Best to get everything right because failed exterior and interior handles leave you with a permanently closed door. Not sure how you open a door with both handles inoperative.