But what about spending gems? I'd say for sure if you manage to spend nearly 300/600/900 gems you should find a way to spend the last few to get it over. If you aren't, then you're not playing CC that seriously. I assume that anyone reading this is going to do at least two quests per day, and log in every day to get the two free eggs.
Then once you have them, spending resources on them. There are two aspects of resource allocation that are related to pets.
That is how to manage pets - where to put them, what to give them resource-wise, etc.
With the advent of pets in Castle Clash, there's a new aspect of strategy to think about.