Booklets and leaflets are impossible to store in themes in the end - you run out of themes or some want to occupy more than one.
If you can use Excel the best way is to create a simple data base (I used to design databases for all sorts of stuff).
When you get a new leaflet that you want to keep just give it a number (the next number in sequence) and write that on the top right corner. Enter that number in the first column of your spreadsheet, the next column should be the title, the next, maybe, the date and then a column with 'key' words - words you want to find that leaflet based on. Now just put the leaflet in a filing cabinet draw or a box in number order.
When you want to find something (say a paper on antelope horn) you just search your spreadsheet for the word antelope and keepgoing through the results till you find the paper you want - you've now got the reference number and you can go straight to it, I had such a system working for technical files that had years of papers in and it worked well.
Actually, you can do the same in Word or any other software that allows columns and search mechanisms.
It is really rewarding burning all the old paperwork. We did a bunch at the start of lockdown. Have loads of space left now. And got to watch some flames. Ditched the cds years ago and replaced them with Spotify. Praise the god Marie Kondo.
Having cleared out two sets of parents homes in the last few years I am determined to make sure I don't leave the same mess for my kids - I just need to know when it's two months before I'm going to kick my clogs
Scan it to yourself - put a copy on the computer AND on a separate USB flash drive.
Oh no, no, no, no.
That would drive me nuts. Themes are easy, they're 'my' themes. I know what interests me, I know how I connect the dots, I know what belongs where and I can find anything in moments.
I don't live a digital world, I live in a very organic one
Paperwork is like a mould , if you let it get a grip it will grow!!!!
Retain paperwork for a Month ( have a pile - paperwork IN , Paperwork OUT ) , get a system and follow.
The digital scanning of paperwork is quick and easy and allows one to access it from wherever you are in the world.
Medical issues whilst on Holiday and lost the paperwork? Just log on an check it out.