Currently, to master an exercise, you need to reach 30 reps or 60 seconds of hold in one session. For some exercises this is fine, for others it does not make sense; we need to tweak the mastery values so that it's a good goal for every exercise.
Since the mastery value will always be different, we'll need to show that value somewhere. I think there are two relevant spots:
  • in the exercise datasheet, on the button that shows how close we are to mastery (and that we click to access the detailed history of that exercise);
  • during a workout Session, in the "Total" section, showing how much more we need to do to master the exercise, or whether it's already mastered. This is the part that will require the most effort in terms of UX/UI design.
Note: also take that occasion to use Time instead of Repetitions for exercises where it makes sense (such as a lot of the high reps cardio exercises).