I have learned that prewound bobbins have more thread on them. That helps. I still run out if I'm not paying attention, I use to have a machine that had a light come on if bobbin was low but it came on when there was still enough thread to keep sewing for a good distance so I ignored it for the most part. Always a con with a pro isn't it? I read somewhere that if you wind your bobbins using a light color thread then use wash out marker to color the starting thread. When you see that color you know to stop. When I'm using my FW I use a full bobbin as the thread spool along with a full bobbin, When the upper thread bobbin gets low the bobbin is too.