If you're having trouble with your Greenworks trimmer line breaking, there are a few things that could be causing the issue. Here are some possible reasons why your trimmer line might keep breaking:
1. The trimmer line is old and needs to be replaced. Over time, trimmer line can become brittle and more prone to breaking. If you've been using the same spool of trimmer line for awhile, it might be time to replace it with a new one.
2. The trimmer line is too thick for your particular model of Greenworks trimmer. Different models of Greenworks trimers take different thicknesses of trimmer line. Be sure to check what size trimmer line your model takes before purchasing or replacing the spool.
3. You're not holding the trimmer correctly while in use. Believe it or not, how you hold the trimmer can affect how often the trimmer line breaks. Be sure to grip the handle firmly and keep the cutting head perpendicular to whatever surface you're trimming for best results and fewer broken lines.