I have 17 years and have done with dogs Flexi as "long lunge" the best experience. I use the canvas several times a day and for hours. The first Flexis are gone after two-three years, mostly on the holding spring broken (ie, the line was not caught up) or torn. These difficulties were apparently resolved. It came to 4.5 years to a new machine because the carabiner has worn. Otherwise, the line was still fully functional.