Bump this thread, since the free Jonin medal event came now we know when to use those stamina pots. Good think manage to saved 42 (50) pcs.

More like getting items from sweeps and exchange them for event ninjas. Although some events have sweep cap like the treasure key event were you only get 10 per day from instances. Other than that just wait another free medal event and spam all stam pots to lvl fast.