I went to sea with BP Tankers as a deck cadet in 1976 trading worldwide, largely to escape my small village life. When I qualified as 2nd mate, I moved to mediterranean trade small bulk carriers, then oil rig supply ships on the North Sea. Got my first command at 32 on the rig boats, so around 14 years at sea by then. Ended up on local ferries when I became a father in order to do shorter trips away from home (I had to drop two ranks, but it was worth it). The biggest crew I captained was around 40 when working on a short-lived cross channel ferry service from Weymouth to Cherbourg. Rig boats typically only had about 12 crew though. My last seagoing job was a harbour pilot for a couple of years which gave me the spare time to learn software dev.

And yes, I was probably one of the last generations of seafarers who used celestial nav and paper charts on deep sea trips before GPS became universal. We used Decca Navigator for coastal nav, now also long gone and forgotten. So electronic charts were way after my time! I lost count after 40+ countries visited, but it's really not the flex you might think because there was very rarely time to go ashore.

However the experience and confidence gained at sea helped enormously when (say) presenting a software proposal to CEOs and the like, most of whom were the same age as me. They tended to assume I was much more senior than I really was! I never regretted the jump though. If you can make the money work, then I’d recommend career changing to anyone for the new lease of life it gives you. Especially if feel you have gone as far as you can in the old career.