Thanks for your input. I think dust is actually a common complaint with these particular controls. In my own experience, I bought these second hand, and initially the z-axis didn’t work right (the cursor’s movement was really finicky and jumped around a lot). After cleaning the sensor with some rubbing alcohol and a q-tip, it’s been smooth sailing, but taking apart and re-assembling the joystick is something I’d like to avoid going forward if I can help it.

You’re right about the cost of those dust covers being a tad steep, but if I could find something for closer to $20, I’d spring for it.