I have slowly been getting rid of papers I don't need anymore, where "slowly" includes going through some stuff and then stopping for long periods. Last weekend I was talking about this, and some of what I had done recently, and that I had hit an entire box full of old letters, and hadn't even taken a deep breath and checked whether it was that or another ten years of extremely out of date bank statements.
papersky started to offer me advice/support about not needing to keep so many old things, and I explained that I knew this already and being told again didn't help. But it turns out not to have hurt, either. With a few days more time between me and opening that box; the desire to stay in the air conditioning today; and an attitude-shifting post from
green_knight, I took another stab at it. Green_knight's suggestion (which wasn't intended as such, she was posting about her own current decluttering) is not to set any goal of how much to get rid of or how much will be left, but to think in terms of looking at things, with "decide later" as explicitly allowed, and counting any amount > 0 of things gotten rid of as an achievement, rather than having to get rid of at least a certain amount to count the project as successful.
I didn't open most of the envelopes, just looked at who they were from. I kept a bunch of letters from my best friend from high school, who I hadn't even thought of in years, and threw away everything from other people I knew in high school. I saved a few letters from my grandparents, a couple from someone I dated in college, and a few others. A lot of other people's letters, I didn't feel the need to keep: I hadn't so much made a deliberate decision back in the 1980s, as thrown a lot of things into a box. (Mostly it's letters from specific people, but I also found a grade report for a college course I took my senior year of high school; I thought briefly about hanging onto that and then remembered that I have my B.A., so transfer credits don't matter.) The startling thing wasn't the random "why do I have a postcard from this person?" but "who is this person who I keep finding letters from?" Names that ring no bell at all, but apparently 25 years ago we corresponded regularly enough that I've got a dozen envelopes with their return address.
At some point I may look at the letters I kept; for now, it's enough to know that I have these. But right now, a third of a shoebox full seems to be enough, at least from that epoch. (Maybe I'll flip through the stack of fanzine letters of comment on the bookshelf and try consolidating.)