I played electric and upright bass regularly for about 20 years, starting around 1996. I even studied upright at a university in my 50's for a music degree. I am in my mid-late 60's now.
Upright bass was becoming physically more difficult. I tried smaller uprights, easier to play strings, a variety of electric uprights, and various chairs/stools for sitting while playing, but with spine issues, playing was getting more painful. With electric basses, the last being a less than 5 pound Hofner Ignition bass, that I actually played at a gig last night I found that even with the lightness, low action, sitting while playing, and flat wounds, I woke up in great discomfort following the gig with that old, familiar pain related to bass.
Several years ago, I played my last upright gig on a New Year's Eve gig, and decided it was time to say goodbye to DB, and take up jazz piano. Now doing the same with electric bass.
I have been working for years at learning jazz piano skills, have played with some groups, and am currently looking forward to semi-retirement in a few months, with more time to play out and further my musical development. This has all involved a lot of planning and focus, and, fortunately, piano was my first instrument that I stuck with for many years as a kid, which helped make the transition easier and, for me, is much easier on the body. I really miss DB, always will, but it is not an option now.
Outside of spine issues, I am otherwise healthy, full of energy, exercise regularly. Yoga has helped immensely, with special poses for spinal issues, and a more gentle type of yoga that creates a lot of relaxation and also builds strength.
I am currently working full time until February, have delved into some great online learning programs for jazz piano, play music with some musicians who I consider good, and they even want to play music with me, have really worked hard at all of this at such a late stage, but with good learning ability and recall which I attribute to being in a constant learning mode, done a number of jazz piano gigs, and think I am finally getting some decent skills together. Now looking forward to semi-retirement in a few months and more time for music.