Until it breaks and starts double-clicking the whole time. Besides, you probably need some idiosyncratic setup, right? A custom trackball or something.

Mine worked fine for years and I think it was the wheel got clogged up in the end. I wanted to just get the same again but Microsoft had switched for the crappy button-on-each-side rubbish.

A guy at work still has one that he uses daily and it works absolutely fine.

I think I went through three of them before I gave up. Ptsch.