This week people of the LDS faith remember the early pioneers who sacrificed to get to Utah's Salt Lake City valley. Many great, emotional stories are retold from that era, some of which have been made into movies. Where did these stories come from? Journals. If not for journals, details would be lost and forgotten or embellished over years of telling, like the size of the fish that got away.
How are you preserving stories and memories? Get over the idea that you have nothing to say or that nobody cares, and consider it a duty. It can be anything from keeping a daily journal, a weekly half hour of jotting down some memories, or simply adding captions to those Facebook photos you keep posting. Use the date and location features, give a brief accounting of what is going on, and let the appropriate audience know something from your personal living history. That file of photos can also be used to spur memories that can be written down later. Talk to a tape recorder, if you prefer. Set up a weekly email question and answer session with your grandkids or ask questions to a grandparent, where you talk about those good ol' days. Print a copy for your records.
I don't consider myself "old" yet, but I can tell you that there's a lot of things from my life that I've already forgotten. It's a good thing I wrote a life history of my first thirty years and a summary of the rest. Find something that works for you and do it before the memory swims away forever! Someone will be thankful you did.