More of a wwyd than aibu.
My grandparents had a massive book where they wrote every single last little purchase and all their income so it totted up and then saved receipts in an envelope.
My parents saved every bill and letter and contract etc in a metal fireproof filing tin.
I keep most of my files on my computer and backed up via the cloud and the few things I have on paper in a tin and also a spreadsheet on my computer for the main monthly bills but not the day to day stuff.
How do you manage your paperwork?