Yea sure also.
If you find gems, Save them don't waste them on boosting your soldiers or whatever the fk, Keep them for BUILDERS because at the end you really need more then 2.
That way you can work on multiply things for example, I can upgrade all my 3 Canon s at the same time and they will be done at the same time or. I can use 2 Builders for upgrading something that takes 2 days while i keep one for upgrading instant things like walls and so on.