When I first started machine quilting with a regular sewing machine, I used a larger needle. This kept me from breaking so many. I began with an 18 Jeans, which was much stronger. As I got better, I went down. I learned this from Harriet Hargrave (sp?) and it sure helped with my frustration :) I broke many needles!
I know 18 sounds huge...but many longarms use a 20. :) 18 is the most common size used. In my longarm, I use a 16 the majority of the time, which accomodates most threads I use. But if I want King Tut or another thicker thread, it requires at least an 18, or a 20. The larger the needle, the less needle flex - on any machine. It's the flexing that causes breaks, skipped stitches, etc.