If you are considering jumping into Kondo's book and method, there's a few things I think you should know.
1. It's going to get worse before it gets better.
Perhaps this is why she offers the advice that you should fully discard before you organize. And I tried, I really really did. But there's some obstacles! For example my garbage cans can only hold so much garbage (same holds for the trash cans at the pocket park, not that I would desperately take anything there ever...) Also, there were LOADS of things to be taken for donation. (Hmm, come to think of it, she may have told me to identify that ahead of time, too...) And there were things I was pretending to sell by posting witty captions on my moms sale group and people would fail to pick them up and my entry way filled up with weird things. The short version: It's going to get worse before it gets better.
2. You're going to need a sanctuary, and possibly wine.
For me, it was my closet. I followed her instructions and started with clothes and my closet was as close to a magazine spread as I care to get (no one is getting between me and my Princess Leia footy PJs,) Anyway, I am very lucky to have a large and now insanely clean and organized closet. Multiple times during the process I'd retreat from a lumbering pile of towels (every towel?? Are you SURE? Geeze that's a lot of towels.) with a cup of tea or glass of wine to remind myself this is why I'm doing this. Once I got started I desperately wanted (want) to finish. So things not only got messier, I got a bit frantic about it. Sanctuary was necessary. I am lucky I work so I had to leave the house and work, God help the Stay at Home parent who lives in their self imposed prison of purging 24 hours a day.
3. This might actually change your life
I didn't really expect life changing to happen. I mean, every book I read changes my life in some way, but although I was excited to 'tidy' I didn't really anticipate magic. But there is some magic! For me, the magic was the insanely simple sounding idea that my belongs should be taken care of. This is literally so easy I try to teach it to my 3 year old every single day. Yet for some reason it was out of my reach. I actually laughed when I first read that "Every thing should have a home." But guess what? EVERYTHING SHOULD HAVE A HOME! Because then it can go there. And when you need it, it will be there. Everything. And since we've started working on this the amount of times my husband and I have asked "Hey, where is the___?" or "Do we have any ____?" has dropped dramatically.
I'm not done, but I can see the start of the light at the end of the tunnel. And as promised, the process gets easier and more automatic as I go along. I'm still dreading sentimental items, particularly photos, but I firmly believe in the principles and the process.