My dealer shamed me into being much more diligent about cleaning out my bobbin assembly. They threatened to take my new machine back if I did as poor a job with it as I did with my first machine!! (They were kidding....mostly.) I don't clean it with every bobbin change though, I clean it probably once in the middle of a quilt and then again when I'm done - maybe once more somewhere in there if I'm using linty thread and/or flannel. I don't think I EVER properly cleaned out my first machine though, so that's a HUGE improvement! I thought occasionally blowing on the bobbin case was enough, LOL. And I shudder to think how old & dull the needle in that machine got. I plead youth & ignorance!
Although, my first machine does still work perfectly! It's a simple Kenmore/Janome from the mid 90's and built like a tank. I expect it'll outlive me, especially now that it's a backup. And that's with me sewing all kinds of crazy craft projects on it, some so thick I had to crank the wheel manually to punch through everything. What a great & forgiving machine...I'll never get rid of it!
This thread made me go change my needle in my main machine a moment ago, too. LOL