Sorry for the delay..
'Overtime' meant that I never unplug the other one for a long time. You can still use the keyboard even it's plugged in, just don't leave it like the mouse. At first I didn't notice it until a year later that some keys like my 'M' and '<-' stops working. When I unplugged it, the problem disappears. Just been happening lately.
Bottom line is don't plug it when you're not playing games and when you're just using Workbench.
I'm using Sega pads cause I have nowhere to buy Amiga pads in a mall here. It's my alternative. If you still need it, just do my advice. :-)