After a while with playing drums, your ears will be of great help in tuning.
I on the other hand, had an ear operation some years ago. The drum dial is a useful tool to get the drums within the tuning spectrum. After that, you fine tune them to your taste.
The dial will help you get to tuning by ear after training your hearing becomes accustomed to that point. It's a training tool and it's very useful.
Check out the tuning chart when you get the chance.
Tuning Chart