The life-changing Magic of Tidying up: The Japanese art of decluttering and organizing - Marie Kondo

She's not wrong. Everyone has too much junk.  We keep it for different reason. For me it is a cross between the ecological disappointment of sending something still useful to the dump and knowing that as soon as I make the conscious decision to trash something, I'll need it and loath to spend money on another of the same after I threw it away.  Donating is good.  Selling is better though.  I've always got some old stuff I"m trying to wring a few dollars out of.  Sometimes it works out well, more often it doesn't.
Many of the things she goes on about I've seen other people do.  I once saw a friend's closet where she had dresses many sizes too small, still with the tags on. It was bizarre.  I've heard people talk about buying stuff on Amazon daily. I mean, no wonder you don't have any money!  These aren't my problem.  In fact, buying things in general is difficult for me.  I research prices until I'm blue in the face, but I am rarely disappointed with a purchase.
The author also has organizational advice that isn't relevant to me as well.  She says that at the end of each day, you should empty your purse.  This way you are less likely to forget something in the wrong handbag the following day.  That would be great if, you know, I had more than one?  Clearly I have purged the maximum number of purses.  (That's not true, I have some from my grandmother, but I'm keeping those for sentimental reasons. They aren't for use. But that's a different topic.)
All this being said, most of her ideas are spot on and as I put my new house away, I will implement many of them, particularly the folding.  When I was moving out, time was limited and I am aware that there are items that made the move who should not have.  I will find them and try to sell them.  I've recently been tracking down a good number of selling locations/platforms and plan to push hard on those. Until and item sells, it will be stored with the other items for selling.  I hope this will keep them in order better.
I'm not into the whole "essence of the home" thing she has going on, but I understand how it could help other people less pragmatic than I.  But the folding, the folding is spot-on!