It all depends on what I'm working on. I had one quilt that took about a bobbin per block, and I'm using the M size bobbins - the big ones, with Bottom Line (a thin thread)! Here's a link to that quilt:

http://wheatridgestudios.blogspot.co...t-is-done.html

Everything in the background of the white blocks was pebbled to raise the design in the middle.

It depends on what I am working on, but I usually fill 3 bobbins before I ever start sewing so I don't have to stop to fill a bobbin. The basics white, ecru, grey, black, I try to have 4 or 5 filled and ready to go. I don't usually keep track of how many I actually use, but I know it's a lot.

WOW !! Have I got a lot to catch up to you all !!!! WOW WOW WOW !!

If I'm piecing, no more than 2 bobbins. If I'm quilting, no more than 6. Longer than that and I get really bad shoulder pain!

Holy cow! That seems like some fast sewing. (Or I'm really slow) If I sew for 6-7 hours, I might use 2 bobbins. Yep, I'm slow :lol:

I worked a short stint in a factory--was faster than most of the workers who had been there for years, but have been sewing---GULP--over 50 years now! My friends say my speed scares them!

Now that would be the best upgrade to any sewing machine.

I just love the larger sized bobbin on my 830 Bernina , i use on a good day of sewing 3 bobbins and if I am heavy in to embroidery may be 4/5 in a day.Just love my Bernina .

I usually use Bottom Line in the bobbin so it goes a long ways as its a finer thread. I still go through several in a day of sewing.

I only use Bottom Line in my bobbins
I can do a twin top with one bobbin