What to Do When Something Is Squeaking Loudly in the Wheel or the Wheel Is Wobbling?

After covering 20,000 kilometers on my Meyra Optimus 2 electric wheelchair, I noticed an issue with the left rear wheel. At first, there was a grinding noise, and after another few kilometers, it became more frequent, occurring every few dozen kilometers. I continued using it, covering over 100 kilometers. One day, as I started moving, the grinding was louder, and it was clear the wheel was wobbling. I didn't feel safe heading out in this condition. I suspected the issue was with the bearing.

When the wheel was removed, small balls fell out of it. It turned out that two bearings were completely worn out. Buying new bearings cost me 30 PLN (September 2023), and the removal of the old rings and installation of the new ones was done as a favor.
I'm not surprised the bearings wore out after so many years and kilometers. I hope the new ones will last as long as the originals.