I cleaned this before I did a king size quilt. This fluff is all from that. I was shocked how much was there. When I took the bobbin holder out - it was a layer of felt under it too.

I clean that area daily and bobbin area each bobbin change on my LA.

Amazing, isn't it??? I clean mine about every other bobbin change when doing the quilting and a little less often when just piecing.

Every bobbin change...

Yikes!

I now clean mine out after every two hours of sewing. More or less.

I remember when I first got my first machine I didn't even know you were supposed to clean it. I happen to be in a dealer's store and noticed her taking off the throat plate on a floor model that was the same as my machine.
She kindly showed me how to do it.

I went home and removed the throat plate on my machine.
And it looked worse than that picture above.
PACKED solid. No wonder it was making all kind of weird noises. :roll:

I clean the bobbin area every time I change it and take the plate off (the part under the needle) every time I start a new project.

Depends on what I'm doing but for the most part I clean with every bobbin change and between projects. If quilting, I also remove all the plates to clean and oil every other bobbin change.

That's my routine as well, although if I'm working with flanel I'll do it more often.

And it's one of the things I hate about my new Janome 6500. The throat plate is a PITB to get off. My Husky is a lot easier.

Every bobbin change.....

This morning, though it was not as packed as your machine.

Cheers, K