A few months ago my old trackball - a Logitech MX Ergo - started
dying.  It was only a few years old, so I was a bit upset.  The
Kensington Slimblade I was using at work was also becoming defective,
but it was almost a decade old, so I found that more tolerable.
Browsing cyberspace, it appeared that Logitech's manufacturing had
finely been optimised to the point where the durability of their
products only just exceeded the warranty period, so the thought of
buying another one didn't excite me much.

Instead I bought a Ploopy: https://ploopy.co/ The name is funny and
it's made by people who clearly like trackballs way too much.  I was a
bit skeptical at first since the plastic parts are 3D printed, and I
tend to prefer the feel injection-molded plastics.  Still, sticking it
to Big Trackball seemed worth it.

I was a bit dubious when I first started using it.  The plastic *does*
feel weird, but mostly because the texture is unusual.  It's not
something you notice in daily use, though.  The actual ball is nice
and very large, but it rests on physical bearings, which I've never
experienced before - most other trackballs use tiny nubs of synthetic
ruby or similar.  While the bearings are relatively noisy, they are
far more smooth than I expected - smoother than normal trackballs for
sure.  My suspicion was that they will require regular cleaning, but
cyberspace actually claims the opposite is true.  Maybe the fact that
there is not a single tiny point to clog up means they're lower
maintenance.  I have yet to clean them even once, and the trackball
still operates as if new.

So in conclusion: the Ploopy trackball is not particularly pretty, and
superficially it doesn't look very good, but it is pleasant to use and
I *think* it is actually much more robust than it looks, and I *know*
it is quite repairable even if it does break.