After years of having a permanent paper mountain, I am happy with how I now manage the paper in this house. It might not work for everyone but there might be elements of it that help you out. I cannot get to grips with using electronic diaries, or photographing documents etc. I work best with paper.
When paper comes into the house it goes in one of three trays that sit on top of each other. 1)to do, 2) keep for reference 3) file. If it's for the bin, it goes straight in the bin.
To do: If it's a form to be filled in or a bill to be paid that isn't set up on direct debit, (eg variable childcare), car insurance reminder, etc I do it when I get a chance, usually once a week.
Keep for reference: is usually information that I will need but won't retain right now eg school trip info, so that goes in a folder set out with dividers for months and 1-30 for the days. I put it in the correct month and then when that month rolls around it gets put into the right date. I have 3 children at 3 different schools and they all do a lot of outside school clubs so there is a lot of paperwork from them.
The file tray builds up and when I'm in the mood I file it. Some of it is kids certificates, school reports etc. I have a ring binder for each child and file in date order. That will be given to them when they get their own place, I don't have a mountain of kids paperwork in the attic.
I have a box file for appliance manuals and guarantees. Go this maybe once a year and chuck ones that are no longer needed.
Essential hard to replace stuff like birth certs and passports are kept in a metal fireproof cash tin. This tin basically contains what I don't want to burn if we have a fire.
Aside from this I have a piece of furniture that is a filing cabinet but doesn't look like one. In there I keep things like medical reports, inland revenue paperwork, annual bank statements, legal documents like my will, local takeaway menus, car docs, etc etc etc.
It doesn't take much time to keep on top of once I got my system going. We all know where to look for a specific piece of paper and find it within minutes. It also stops the "I'm sure my car insurance is due but can't remember when or find the paperwork" panic. That is worth all the setting up time imho.
Oh another thing I do...Important receipts that aren't emailed are stapled into a week to view diary in the relevant week. This way I can return stuff if it breaks before reasonable use. Prior to my system I would have given up hunting in the paper mountain after a couple of hours.
Reading this back it sounds more faffy than it really is. 😖 But it works for us.