For me, after years and years of being unsuccessful at getting and keeping paper organised, I have come to the conclusion that as I am basically lazy and dh is too, we need a system that is sooo easy and fits the way we think.
My fil recommended getting box files as you can just chuck the paper in and then when you need it, or have time to do a cull/sort, you just leaf through. He reckons it takes longer in total to decide exactly where each particular paper goes and find that place and put it there than to find a utilities bill in a box of similar ones on the rare occasion you need to find it.
What exactly do you need to be easily accessible and sorted? We have one box labelled "Personal & Car" that includes a wallet of identity documents so we can get that quick. Then we have one box for Money, one for House and one for Info (including important instructions and warranties). Those box files are in a kitchen cupboard that also has a set of trays for Action, To File and In Use. I did include a need for that cupboard when designing the kitchen though!
In theory, I open post immediately, shove it either in the trays or in the top of the right box file if I have time. And then sort through the boxfiles and archive anything still needed to the loft once a year. Very rare that you actually need to lay your hands on a bank statement from 2 years ago quickly, even though you are supposed to keep them.
I still have a box of random memorabilia though that needs to be sorted and I just can't decide how so I'm waiting till inspiration strikes. There's no rush. It's is in a box and can just stay there a while.
Now to confess - the reason I spent this time typing out pretty pointless advice is that I am SUPPOSED to be sorting the paperwork today! We have 2 days post in the porch and a weeks worth on the kitchen worktop because sleepless nights with a toddler and a baby crushed my energy levels. Oh - and I blame my mum too!