It may have to do with rehearsal of memories. Some people go over and over their past, recount it often in stories told to others, discuss it with people who were there at the time. Others don't dwell on the past, don't often review it, and focus on now. It may require some repetition to engrain memories long term and keep them fresh. Although other research suggests that every revisit of a memory alters it somewhat, is a rethinking of it, and the rethinking is remembered instead of the original. Eyewitness testimony in court is notoriously unreliable. Everyone has their own contexts and remembers events in light of those contexts, rather than what actually happened. One person remembers it was a fun party, another that it was a dreadful party.
