Best of luck! I love your description of his perfectionism – I am very similar, and while I admit I have a big problem, I think my problem is different to “being lazy”, and that fixes (however well meant) for one won’t necessarily fix the other.
What I suggest for a system is something which (a) is easy to implement and (b) is extensible. Like, “For now, we’ll put all the banking stuff in this file, but if it’s bigger than 20 things, we’ll separate it into two.” I found justifying “good enough” really help me get started. The key for me was not choosing a system where I’d deliberately never get it “right” but choosing one where a good start would fix 90% of the problem, but was always open to small incremental improvements (if we have the time) or not (if we don’t).
The key, key, KEY responsibility for your file system is that it should be simple. This is so that when you get a new piece of post or whatever, it takes 2 seconds to put it in the filing system. If it takes longer than that, you’ll put it off.
The other thing that helped me a lot (don’t know if you need it) is to take any existing large pile of unsorted stuff that’s been hanging around for ages and put it aside with a note on top saying “unsorted papers, as of [today’s date]” and then file everything NEW immediately. Starting with a clean slate makes it so much easier to sort new stuff. And then you can sort the old stuff when you have time (or if it’s just junk, say “I didn’t need this for the last two years, so I’m just chucking it”.
For an actual system, do what the other people suggested. Their categories are way better than anything I can suggest Basically, buy a concertina file or filing cabinent or whatever that’s large enough. (KEY POINT: large enough,. If not, it’ll be full and you’ll never put anything in it. Don’t live with a full filing thing you can’t add stuff in. Throw stuff away if you have to (it’s better than losing imoprtant new stuff). Buy more space if you have to.) Then designate each file to hold one sort of thing.
The only thing I found difficult was deciding how much there should be a folder for “important stuff”. Originally, when I got my first job, there was one file for “birth certificate, driving license, job contract” and little else. Now that’s split into “personal id docs”, “driving stuff”, “job #1 contract and salary stuff”, “job #2 …” “job #3”.
Out of interest, what sort of professional organiser did you find? I’m curious what’s available.