I posted several weeks ago a few tips on machine quilting. One of those was how important it is to change your needles regularly. Here is a perfect example of what happens to needles over time and the difference it can make in your machine quilting.
The first picture shows machine quilting as the needle has started to go bad. You can see the bobbin thread showing at the points in the middle section. I had been using this needle for over a week, working on several small projects but doing over 10-20 hours of quilting and sewing. This morning I stopped to mend my husbands jeans. After mending his jeans I resumed quilting with the same needle and all of a sudden I am getting the bobbin thread showing on the top of my quilting. I of course stopped, changed my needle, cleaned out the bobbin area and resumed quilting without touching the tension. Miraculously the tension was corrected. Right picture.