Assuming you're middled aged that is: PLoS Biology: Gene Expression in the Aging Brain.
Recent articles claim that while the average age of non-neural tissue is 10 years, brain tissue age matches chronologic age. (Yeah, a few years ago there was a claim that brain tissue actually regenerated, but that's looking like wishful thinking now.). Now it appears the frontal lobes, the seat of judgment and foresight, wear out fastest.
Brain rot. It affects all of us, and it starts in our twenties. By our forties our brains are definitely hurting (quick, get into management!) and by our sixties we're ready to retire -- except, oops, we can't any more.
There will be a lot of fighting for those grocery bagging jobs @ 2020.
In the meantime, despite all the 'use or it lose it' cliches, it's worth noting that this decay of the frontal lobes (aka, the person) may be related to protein oxidation -- which is related to mitochondrial activity. Perhaps it's better to give those lobes a rest. Stop reading this blog and turn on the TV! Or better yet, go to bed.