Good thread!
I've been retired almost 6 years. My retirement plan was/is more riding which has been happening. Moreso on my DR and S10 that Bergs though.
Last job was Dam Safety Analyst where I morphed my civil engineerring, surveying and IT backgound into extracting data and morphing it into information. Which then leads to knowledge, followed hopefully by understanding, then followed by, for a special few, wisdom.
data - information - knowledge - understanding - wisdom
One of my jobs was training up the data collection guys and attempting to get them to understand things like the difference between null and zero, and that if the data they collected was flawed, everything that followed was also flawed.
Challenges and mental stimulation almost every day back then. Still occupied with volunteer work and adventure riding, and the odd bit of contract work. Not too many/any around with my skillset.