I have two machines, a Singer and a Brother. I use the Singer when I am volunteering at the middle school with the fifth-grade quilting project. It can travel without problems, and it is relatively kid-proof. The Brother is my go-to home machine, which I use for quilting, sewing, hemming curtains, etc.
Although they look identical, the bobbins for each machine are just different enough that they cannot be interchanged. It only takes a couple of stitches for me to realize that I have mixed them up. Believe me, it's a pain to have to rewind a bobbin from another one, but it does make a big difference.
The dreaded "felt" which I make in the bobbin area has caused me problems, also. I don't want to take the time to clean everything out regularly. It takes to much time away from the actual sewing. However, I have to force myself to clean out the bobbin area more often. It, too, makes a great deal of difference in either machine.