Our daughter graduated from high school in 1987. A group of her friends were at our home at that time and made predictions about their future lives and gave me the list to keep, planning on getting together in 1997. (I am the ultimate home file keeper.)
I filed the paper, keep it, look at it every 5 years when I purge my file cabinet then remind daughter. No one seems to care, but I feel obligated to keep the darn thing.
When we first bought our vacation home 40 years ago and were decorating for Christmas, I got the kids' craft supplies and a paper plate and constructed a very passable angle tree top - we were all amazed. It sat on the top of little camper tree for 20 years, long after we had small 'real' ornaments and could have afforded much better. It finally got wet and kind of disolved a couple of years ago. We all mourn it.