What are you learning?
Most of us are discovering that we didn't know everything after all. We did when we were younger, but now we don't. There are various physical conditions of brain maintenance that result in disorders that are currently poorly understood, such as altzheimers and what they used to call senility, but research does indeed point to keeping the brain active by continuing to learn things as a contributing beneficial factor. Plus, we're the kind of people that would be doing this anyway.
What are you learning at the moment, these days, this year? Not necessarily iOS music related, although it could be, or could touch it tangentially.
One thing I might chuck in here: the things I'm learning these days have a 'circle completion' aspect. When I was young I was into various interests, some of which stood me in stead to earn a living. I didn't fully learn those topics, I stopped when other people thought I knew my onions. I suspect a lot of people out there in real jobs are similar charlatans living in fear of being found out. I've no idea how I fell into this pattern, but what I seem to be doing is to rediscover areas of interest that I had when I was much younger, and revise up on them, catch up to the knowledge level I used to have, then exceed it and learn all the stuff about it that I basically skipped or faked, the first time round. It is very much like going back to school, only this time, paying attention.