I had never heard of this until I went to drug rehabilitation. But it is not a practice limited to addicts. It can be a tool for growth and expanding your awareness no matter how you arrive at the practice.
If you have ever quit using mind altering substances after any period of time, you know that it can be a desperate, lonely and overwhelming time. It was suggested as a method to try (as was keeping open-minded) and I was sick of feeling awful inside and would have tried anything to help in the new, raw and vulnerable position I found myself.
I started small, with 3 things every day. The idea is- even if it seemed like everything was coming down around you, and let's face it, when you are in rehab, it already has, you have to keep up with it every day. I kept to it most of the 90 days. It made me feel good to accomplish something and hold myself to something more than just not doing mind altering chemicals. I had expanded it to ten by the time that I left and came home. I might be giving myself too much credit to say that I kept it up for 2 weeks after leaving, but I didn't make it as much of a priority as I had before.
This is not a relapse story. But, I did part ways with the practice. I am not going to say I didn't need it, because I did, but I let it fall away from my mind. My mind has not gone to the negative, hopeless and desperate state I once found myself, but negativity DID begin to creep back in, slowly and quietly, as it often does.
Fast forward a few years and I have started keeping one again. This time, however, I began to use it as a tool for growth. I write down between five and ten things for which I am grateful every day. Yes, I miss days. I am not perfect. But the INTENTION and effort expended at BEING grateful and living grateful has been greatly rewarding in my life.