I could never go that long without cleaning in there! That wasn't lint, that was felt!!
I clean all my machines in the bobbin area with a Q-tip every bobbin change, and add one drop of oil. Because I do it so often, there's very little lint in there, and it only takes a few seconds. I also oil the bobbin area at the start of each sewing session. Even the new sealed machines (which don't have to be oiled) need the bobbin case to be hand oiled often. It is separate from the rest of the machine, so if you don't oil it, there is no other way for oil to get in there. It's the best thing you can do for your machine, to keep it running right and a long time.
