Before I share my thoughts, let us define neuroplasticity.
"… neuroplasticity, the capacity of the brain to develop and change throughout life, something Western science once thought impossible.—Time, 8 May 2006"
-"Neuroplasticity." Merriam-Webster.com. Merriam-Webster, n.d. Web. 20 July 2017.
To flesh out the idea, your brain is constantly in a state of change. The change is physical and is influenced and guided by what it is doing on a regular basis. The brain is constantly trying to get better at what it does, and is willing to lose other things it has learned in order to do so.
The brain consumes a lot of energy, 20 percent of your total energy consumption according to https://www.scientificamerican.com/article/why-does-the-brain-need-s/. It is constantly trying to make things more efficient for itself to operate, and one thing it does is prune itself of irrelevant information. The actual structure of your brain is altered and over long periods of time it can even change shape.
The neural connections in your brain strengthen the more you use them, and the less you use them, the more they shrink and wither away.
Quite literally, the saying "use it or lose it" applies to your mind.
Keeping neuroplasticity in mind, it can be said that every single moment of your life you are actively creating the you of the future. Your brain is constantly "taking out the garbage" if you will, and the garbage is whatever neurons you don't use. It is changing its physical structure to become better and better at whatever it is that is being done.
When I think about people that do nothing, people that say they're tired all the time and only scroll through memes all day and don't exercise their mind, it makes me scared for the mental capacity and fortitude of the general population.
Please do the world a favor and try every day to be a superior person to the you from yesterday. In this effort, perhaps we can create a better world filled with mentally potent individuals.