I wonder what the items are? Are they sentimental items?
I'm very organised but I have to be ruthless on some items. I don't like 'clutter'.
We like to travel and we kept a lot of memorabilia from places we went to for 'the first time'. We made albums which we called 'The Books of Firsts'. They contained photos, leaflets, itineraries, tickets etc.
I'll only occasionally flick through them now but I found this to be a good tip: take a photograph of the item instead of keeping it. A photo takes up a loss less space.
More recently I had some things that were my Dad's (my Mum asked me to take everything that was my Dad's out of their house after he passed away). I donated the bulk of it to charity but there were some things I couldn't part with (yet I know they are of no use!). So I've kept his glasses/glasses case, his favourite shirt, a stash of paperwork he kept when he went to New York (his favourite place), a few books and some cards.
I had still got my Dad's wrapped Christmas presents that I bought for him (that he never got to open); I kept those untouched for a while, but I unwrapped them myself last year and donated those to charity too.
I think a lot of things that we treasure, won't be treasured by someone else so perhaps we should just enjoy them in our own way.