Keep playing, or wait for keys to open?
So I just downloaded this game and it's quite fun. Of course, all my keys are full in about 10 minutes - so I must ask, play tomorrow, or keep pushing? I don't want to have underleveled troops in campaign/arena because I didn't wait for chests to open... Is there any guides on the key system? I want to play more than 10 minutes a day lol.