For me I have found thread tension a problem with all machines. Especially if you use non matching thread. Such as Bottom Line with a different top thread. These problems don't just start at the beginning, they develop! So keep checking your tension, on the bottom of the quilt, and the front. Oil your machine every time you put new thread in your bobbin. ESPECIALLY if you are using Bottom line, embroidery bobbin thread or a thin thread. I keep a cue tip by my machine and dab some sewing machine oil on the cue tip. Then when the bobbin is out I swipe it around the pin that goes through the middle of the bobbin case. I also swipe the back of the area that holds the bobbin case.
If you are sewing for a long time, make sure you check under the throat plate, mine accumulates lint, clean it out, and oil again, moving parts. You don't need lots of oil, just make sure that the cue tip is oiled and it oils the part you want. Keep it away from computer boards. I had a singer that was made in 1971 and used it for many years. However, it was very loud, and the timing would go out while I was quilting.
When you start making mistakes, and you will. Stop get up, take a break. You are tired. You can't expect the machine to work non stop and not make mistakes--and in this case the machine I am talking about is you. If you start having problems with needle breakage take a look at your throat plate. Do you see some little nicks? That comes from pushing your fabric or pulling it too fast for the machine. Ask me how I know? Pam Holland doesn't drop her feed dogs when she free motion quilts. I have tried it, it works, just try what you like, and work from there. Good luck.