Yes, I was taught that many years ago. You should be able to hear a difference in the sound unless your DSM runs on silent mode.

Love the machines that tell you when you're running low! Or I'd be doing the same thing.

I sew more in spurts so don't go long time with no bobbin thread. Time for me can be measured in inches or feet, never minutes or yards. I can't imagine chain piecing 15 minutes with no bobbin thread. I actually can't imagine chain piecing 15 minutes period. The quilts I make don't have a lot of chain piecing. When I do it is for just a few pieces and then those are assembled into a block and I repeat the process. I can't keep the orientation of pieces correct if I get too far ahead of myself plus I like variety. I cut a little, piece a little, press, put on my design wall, question my placement and color choice, rearrange, assemble in block, repeat...

My bobbin loads from the top, so there is a clear plastic "window" which allows me to see the bobbin. I've made myself check the bobbin occasionally just to be sure there is thread on it. I still sometimes run out, but at least I can try to predict whether or not I can make a particular seam before "sewing air."

I have an older machine...it doesn't have a bobbin out sensor, nor can I see the bobbin. I'm not likely to notice a change in sound when it's getting low, although sometimes I do.

A trick that I read on here is to use a wound bobbin in place of a spool of thread. When the 'thread spool' bobbin runs out, so has the lower bobbin. :)

Been there, done that, although I try to put in a new, full bobbin when I begin a project, it doesn't always happen, but I try. I'm looking forward to your finished quilt.

I let that happen once. Lol. I was chain-piecing my rag quilt squares and got thru about 5 of them before I realized it was out. Ha ha ha. Smack myself in the forehead moment for sure!

welcome Knitwitrosie

I finally (HOORAY) got a walking foot for my little Janome Gem Silver Limited Edition. there is no way I can hear the difference in the sewing now. The foot makes a rattling sound when it's on. But there is no way I'd trade it for love now money as the saying goes. I am in love with this $50 walking foot!

If you start out with a full bobbin in the bobbin case and a full bobbin on the spindle in place of a spool of thread they will not run out at the same time because the top one will use more thread as it loops around the bobbin thread. It certainly gives you a closer approximation than just using a spool of thread but there is a difference. I often use a bobbin in place of a spool of thread if I want to use it up. When I'm piecing I'm not really fussy as to what color I use since it won't show anyway. The more money I save by being thrifty with thread the more I have to spend on fabric!!