We don’t want to get all technical here, but really there are few worse sins than using your hard earned rubies for no reason.
Rubies for elite account
Controversial point: New accounts can’t buy elite account status, but by far the most effective use of rubies is to do just this. 7,900 rubies gets you elite account status for a whole year. Perfect. Now you get 75% extra XP and 35% more resources as well as being able to build two buildings at a time.
Rubies for wood/food
In all fairness, there are times where using rubies for resources makes sense. But really you want to be using this option as little as possible as it’s bloody well expensive. If it’s just a few gems, go for it. Especially if you have hundreds of thousands of resources and you’re under attack!
Rubies as speedups
You should never, ever use rubies to speed anything up directly. You are always by far better off going and spending those rubies on a speed boost pack at the forge for 1,750 gems and getting 10x 12 hour time boosts.
Rubies for tokens
If you’re fortunate enough to have an event with double tokens, then this is where you should be investing rubies. The main source of reward in this game is from solo rewards earned from events. Since the events rely on your power (and therefore dragons), having as many tokens available to breed the best possible dragons is a great course to choose.
Choosing the shortest mission timer will give you 1 token per ruby spent (regular) if you have an elite account and is far more ruby efficient than speeding up the hardest missions which give 0.2 tokens per ruby spent.
Obviously all of this is going to be down to personal taste. As you need higher levels to get access to more powerful dragon tiers, sometimes you are going to want to blow rubies on time boosts instead of gaining tokens.
Spending speed boosts
If we had it our way, nobody would spend speed boosts on anything other than buildings. Leveling dragons is slow, as is hatching them. The only time we recommend using speed boosts for hatching dragons is where you simply have to breed a dragon to gain access to another dragon during a breeding event.
Even that is tough though as higher tier dragons might not even get enough experience to breed before the end of an event.