For me, I save my sketchbooks (I have a huge tub of like, 40 of them???) but anything not in the sketchbook gets sorted into the "keep" or "don't keep" pile, and knowing that I have sketchbooks that're like....representative of most of the eras of my life, it's a lot easier for me to throw away loose sketches. I'm very attached to old work and keep lots of it, but you know, there's that whole "where your treasure is there will your heart be" thing, so I consider it really important to be willing to get rid of it if I need to. ;u;
Consider that if you save LITERALLY EVERY SKETCH, it becomes actually really hard/impossible to sit down and compare your new work to your old work. If you can look back at the top twenty drawings you did ten years ago, that's awesome. If you have 500 sketches to look through, you're more likely to just have a huge drawer full of paper that you're like "yup, my sketches sure are in there, it would take two days to go through them so I'm not going to look at them, but I sure couldn't bear to part with them." That's not doing you any good. 100 sketches you have time to look at is better than 500 sketches you never do.
There's also something to be said for cutting down your collection to something you can reasonably manage to preserve! Inks fade and pencils smear -- if you have more than you're able to take good care of, you're not really saving any of in a long-term way!
I do like saving physical work, but if you're gonna do that, you gotta be able to sort it a little. You're only going to make more!!