Well it really depends on how many shards you need. Consider the odds. You will most likely get something like 3 shards for a refresh. Will those 12 shards have an impact (4 days remaining roughly) and could they get you to 5* (I assume). Then your Yoda was 1600 Crystals more expensive (more than he was already spending 200 on energy refill). Only you can answer yourself that very question.
As long as I clear 300 crystals for an arena reward i do 100 and 200. 400 seems... excessive. I don't think I'd even do the 200 if arena wasn't supplementing me.
Replies
Slower is better.
You sound like a weaker. lol Either go hard or go home.