For the past few years I have been dipping my toe in Marie Kondo simplification and tidying up. Doing this I was able to let go of a ton of unneeded stuff, in particular clothes and books. But I still have a lot more to let go of and periodically I do some "Konmari-ing" to clear out more space. This remains an ongoing activity.
I recently found the website of Rob Greenfield and have become fascinated with his minimal lifestyle and his activism. He lives an extreme lifestyle which it is not for me (or most people I know), but he has some interesting ideas and insights. in the video below Rob shares some practical techniques for removing unnecessary stuff from your life.