Board Thread:Eureka Moments/@comment-24235936-20170716182716

If you are close to leveling up, don't waste a large booster. Use a small one, or try banishing monsters or trading to get just enough energy to level. Your energy will be completely restored when you level up.

If you are less than 150 XPs from leveling and have lots of energy left, play the most expensive room you have enough energy for (usually one from a former Challenge) to use up energy and get your next level off to a good start. This is a great time to hire an Accountant or Keeper too. 