Can one ever be "done" in this hobby?

I too still like to keep up with new innovations or products that might add value even after having identified and actually "hit the target". I also actively look for every opportunity to downsize and still hit that target or at least come close enough that it does not really matter.

Like Martykl, I count many (about a dozen or more different ways) I might listen to music these days, both in and out of the house, so lots of opportunity to just listen to more music in different ways, in different places, play around, and experiment.

Assuming one cares, once you know what your target is and you hit it, its harder to change than not.

Otherwise, not so hard if you are not hitting the target or the target constantly moves.

Then of course most things break or wear out and eventually just need to be replaced, assuming again one still cares.

To each their own.