I bought a pair of Cat Eye bike lights and a pair of Nite Ize clip on lights a few years ago. I had a red one on the back of my rucksack and a white one the front of my coat. My wife was set up too. We don't walk to/from a train station in the dark any more so they are currently spare.
Since we don't use them ourselves I've attached them to my mother-in-law's dog's harness so we can see him the dark. The Nite Ize SpotLit failed first, it just couldn't stand up the constant bouncing motion from an excitable dog. I swapped the it for this Cat Eye, which was attached without flapping, so has lasted much longer.
The Cat Eye failed, though in this case it's a previous repair that has failed, and the solder has broken free, as you can see here, if I bend the LED a little contact is made and it works, but any movement and it breaks the contact and the light goes out. That will be another solder job to do.