I've never been able to hoard and keep up with my energy refreshes consistently. When I find myself with 'extra' crystals (like that's a thing) I might use them for CCBs, or even more rarely, kyro if I'm really crunched for it. Spending 600 crystals a day on refreshes can make it tough to save much though. On very rare occasion I'll spend on a pack - like the one the other day that dropped two full G12 pieces for 2k crystals. That one's hard to pass up. Generally speaking though, I'm hard pressed to find a more efficient use for crystals than energy refreshes.
