Minimalism is a goal to only own items that serve a purpose in life.
It's eliminating clutter, things that distract from what really matters.
There's a quote (falsely) attributed to Warren Buffett that says to succeed in life, write down the 25 things you'd most like to do, then cross off all but the bottom 5. The rest are distractions. These 5 are your most urgent goals, and the highest priorities.
(When asked about this, Buffett laughs and says he's never made a list in his life)
You have clothing and decorations and hobbies and tools and kitchen gadgets that improve your life. That make you smile, that "spark joy", that matter.
And then there's the other stuff.
Why?
We accumulate things because it's easier than the alternative. We get a spark of joy on purchase, and then it's gone.
I'm not saying you have to get rid of your books, especially if they bring you joy.
But there's value in curation.
In the early 2000s, I had an iPod Nano that could hold thousands of songs. And I found myself skipping them quite often.
When I burn a playlist of 12 songs to a disc, I don't skip a single one.
Less is more.
See Also
Marie Kondo
Consumerism
Hedonic Treadmill
Minimalism: A documentary about the important things