Very interesting to read all this! I started decluttering several years ago... I bought a little notebook and pledged to get rid of one thing a day and I stuck to this for a long time. Trouble was that there were many thousand things to get rid of and I'd be about 200 years old before it was finished...
Art and craft stuff is my big problem. Got loads of embroidery fabric, threads, calligraphy stuff, knitting wool, paper, card, paint, crayons, rubber stamps, wood, it's just endless. We downsized 6 months ago and I disposed of piles of stuff in readiness so how can I possibly still have at least 20 packing cases of crafty stuff? They are all in a small bedroom where, hopefully, I will work on future projects but it needs decorating. It currently has wallpaper featuring dinosaurs which aren't really my cup of tea! So the boxes will all have to be moved out to a downstairs room which at the moment is stuffed with numerous boxes of books plus bedding, linen, surplus curtains etc from our family home. I kept all this in case our move fell through and we stayed there till popping our clogs and needed it for all the beds/guests. In the end only 8 days between exchange of contracts and the move so it all got thrown on the removal vans and I'm still sorting it all out.
And then there's the clothes... ancient stuff that I live in most of the time, posh stuff that rarely sees the light of day, stuff that's too big but I should probably keep 'just in case'!
Off now to find something to chuck... will follow the thread and hope to be inspired by more efficient declutterers!