I follow IRS rules and keep 7 years of documents. When possible, I have bills electronically sent to me and I simply file them in folders in G-mail.
Each January, I create a new set of file folders (physical) that mirror the previous year's folder structure. Then, I shred the files from 8 years ago. Takes an entire hour. My files for current year and past year are in the top drawer of a 4-drawer file cabinet. The other 5 years' stuff is stored 2 drawers down. The 2nd drawer holds things like insurance info and instructions/directions (indirections??) for house-hold "stuff". The bottom drawer is for home-owners stuff, personal stuff. etc.
My work files are stored under my desk in a double-drawer horizontal filing cabinet. It holds all things work-related. But, the top drawer closest to me holds anything that is currently going on in my life, so that I have instant access when I get phone calls, e-mails, etc. On top of that, I have an organizer on my desk that holds really, really current stuff that would include stuff that I will be working with on any given day.
I have been doing this for years, and it works, as long as you keep a maintenance routine. Easy habits to get into and I am never searching through piles like I see others doing. My desk stays neat and organized and I always have what I need for any day right in front of me.
Being organized like this is essential to increasing personal productivity and producing quality work.
It is stupidly easy, but I would say that maybe less than 5% of people can achieve a high-level of organization.
Your question might come across as dumb to other slashdotters, but I find it incredibly relevant.