It helps me to use a fine thread in the bobbin (Aurifil 50wt 2-ply or polyester embroidery bobbin thread, which is 60wt). The bobbin holds a lot more thread when the thread is fine. I check the bobbin before I start to give me an idea of how much is left. For me, if I have a full bobbin wound with one of these threads, I know that I will run out of steam for a marathon sewing session long before the bobbin runs out of thread. I have found that checking the bobbin *before* I start sewing helps. Nowadays, if the bobbin is low, I will change it out rather than risk forgetting about it and sewing a mile with no bobbin thread.