I had 20/20 when I was 5 or so. I'm not sure what happened; perhaps it was just growing up, or maybe that horrid bike accident that did it; but my vision disintegrated very quickly. Nowadays, I can't see details more than about two inches away, everything looks like a swirling black hole of paint without correction lenses, and my vision is even getting worse with every passing day.
I'm incredibly thankful that I've got insurance coverage for contact lenses, and a future discount on a laser eye surgery. I would consider myself legally blind without vision correction.