I just got one a couple of weeks ago with the idea of wearing it on walks. A few days later, I watched a video with featuring Dr. Sherry Betz (physiotherapist) and she said that walking with a vest was not effective and could overload your joints. She does recommend it for squats and lunges so that is what I will be using mine for going forward. Mine is a Hyperwear vest holding 10 pounds.

Here's the link to the video: https://www.youtube.com/watch?v=ZHlyXu9hQ-k

Discussion of weighted vests starts at 18:20.