I’ve found that most bungee cords wear out, at which point the ends break off or the cords lose their stretchiness. As a solution, I get old bicycle tire tubes free from my local bike shop and cut them into strips. I attach a hook from one of the broken bungee cords to one of the rubber tube strips by pushing the strip through the hook and then securing it with a knot.
You can cut the rubber tubes to any length, and, in my experience, these DIY bungee cords last much longer than store-bought versions.
Remsenburg, New York