I'm doing kind of a modified Kondo (full disclosure, I did not read the book). I think "sparking joy" is a bit much to ask of most objects and is really only an appropriate response for a select few things, like art, perhaps. I am asking myself questions along the lines of:
Do I like it?
Do I use/wear it?
Do I have other things that fill the same purpose/niche?
If I'm saving it for "just in case," how likely am I to ever really use or need it?
I sent 2 boxes and 2 bags to the Salvation Army last week. I'm starting on another box.