Hello, Maggie - We're very sorry to hear of the frustration you're having with the lines breaking or tangling! Auto-feed string trimmers are designed to release about a ¼ in. of the line every time the trimmer's trigger is released. And if a user squeezes and releases the trigger continuously, then more and more line will advance, which can lead to wasted line or tangles. So we encourage you to be mindful of this and avoid repeatedly squeezing and releasing the trigger. And to help make your line last longer, please be mindful of wire and picket fences as these can cause extra line wear and breakage. Also, stone and brick walls, curbs, and wood may also wear the line rapidly. We hope this helps! And if you'd like to discuss your experience further, then please feel free to email us anytime at Reviews@RYOBItools.com.