Some thoughts on whether it is useful to practice on both sides or if it is necessary to reach a state where both sides can perform on the same level

Basic assumption: If you spend your time practicing everything on both sides you won’t reach the same depth as if you would spend your time practicing only on one side (Ressources).

That being said, it really boils down to WHAT you want to reach in your practice, WHY you are practicing and IF there is a special need to be equally good on both sides.

If there is a special need to be equally good on both sides, of course spending time practicing both sides to the same extend makes sense.

In Frank R. Wilson’s book „The Hand“ the author writes a lot about why we as humans tend to have a more dominant side (writing, throwing stuff, etc.). Two main points:
A. If you need to be able to throw real good (fe for hunting reasons) you want to practice as much as possible on one side (resources)
B. very interesting: actually the author does not like to talk about a dominant and a non dominant side – if you think about it, both sides have to do their work in order to fulfill a goal (the free Arm in throwing is being used as a counterbalance, etc).

So, if there is no special need to practice on both sides, why could it make sense to work on the other side as well?

1. If you practice something over and over on one side only, your body will adapt to this stimulus. In some cases this can (not a must) lead to injuries. In that Case it would make sense to either practice on both sides or do another activity where you are working on the neglected side.

2. In many disciplines it can be an advantage if you can do something on both sides (in my practice I have more options this way, in skateboarding competitions you will receive a higher scoring when doing something on the other side, etc.)

What I personally find interesting: instead of reaching a state of equal performance on both sides I like to find different qualities on each side.