I'm not sure when I was introduced to the idea that I didn't need it. That the world wouldn't stop--and in fact my life would get better--if I let it all go.
I just read Lorilee Lippincott's book 3-2-1-Stop which explores this idea. She takes it beyond the physical world of "stuff" and into time, money...and even yourself. I wish I'd encountered this book 15 years ago.
If you've ever been interested in living a little bit freer, this book is for you. It isn't a big complex read. In fact, the style is as simple as Lippincott is encouraging you to live.
It is available on Kindle (the way I read it), in PDF, or paperback. Worth your time...and in fact, may result in freeing up more of it.