Your brain is not in a fixed state during adulthood. It's constantly in a dynamic state of self-repair and regeneration, giving birth to new neurons through a process called neurogenesis. Born in your hippocampus, neurons float around for a bit having a jolly old time and then either die of boredom or get annexed and put to work on a region of your brain that needs them. If they get annexed they form stronger communications pathways in those areas.
If you aim to learn a new skill then you will be increasing your brain's neuronal connectivity, rounding up spare neurons and adding them to your brains 'connectome', or wiring diagram. This will help against the impact of dementia in older age. It won't necessarily prevent it, but if you have a gradual reduction in neuronal activity over time, the more neurons you have, the longer this degeneration will take.
Plus, the more pathways the stronger the neuronal circuitry in your brain and the more capacity you have for critical and creative thinking, logic, memory and reaction times. That could alone save your life out on the road. Or help with catching mice.
5 ways to assist Neurogenesis:
Lots more you can do of course, but it's a start.
This year, save those newborn neurons from a certain, horrific death.
Give them something interesting to do and watch them, and you, thrive.
Probably best not to feed them after midnight though, just in case.