Over time, players may opt to change their Conviction or Discipline ranks.If they improve these skills, it's not a serious source of concern, but if either of those skills are downgraded, or if they opt to modify their Focus Items at an appropriate Milestone and switch out one they needed for a rote spell, such rote spells could end up requiring more Discipline than the player can muster, and becoming unavailable.
Do they get a chance to refresh/upgrade existing Rote spells to match their current capabilities, or are they stuck with the same rote spells they created in their first adventure? I have reviewed the Milestone rules and could not see anything covering rote spells.