As time goes on you'll find that it takes longer to get the chests and crowns you need to maximise your rewards. Of the chests you win, Silver chests have a three hour timer, Gold chests have an eight hour timer, Giant and Magical chests have a twelve hour timer and the Super Magical chest has a twenty-four hour timer.
You also want to get ten crowns per day to unlock your Crown Chest, and once your rank settles a bit you'll find that can take some time to get. It depends somewhat on how aggressively you play, but ten crowns will take some time if you're only winning half your matches. You also get six free chests a day, every four hours, which you can simply log on to unlock, and once you are in a clan you can request a card (ten commons or one rare) every eight hours. Don't underestimate the value of requesting for cards and donating them. Requesting cards has, for me, been the most efficient way of upgrading my common and rare cards.
If you're in an active clan, donating cards is likely to be one of your main sources of income and likely your #1 source of XP (which leads to your towers being upgraded). It is the one thing that makes it worth logging on quite frequently, as the only limit on donation is that you can only donate cards of 60 value per day (common = 1, rare = 10). I would caution you from donating anything, particularly rare cards, that you think you might end up using. You'll regret it later.
There is one other key reason to play, which is to increase your trophies. Higher trophies means higher arena, and higher arena means better chests (they have more gold in them, and they can contain a wider variety of cards as well as actually having more cards in them). If you feel like you could push yourself up to the next arena with a longer session of play, go for it.
If you really hate waiting for chests, you can pay to unlock them with gems but I think it's not particularly efficient compared to converting gems to gold. For what it's worth, I believe there is some indication they may be adding some kind of reward (presumably pretty minor) for winning games even when you have full chests. I suppose there will be an update coming in the next few weeks, maybe it will have this.
