I'm not sure. Maybe it's because I have a poor memory to begin with, but I just don't see the reason for this. It reminds me of older people (mind, I'm over 60 myself) who spend all their time reminiscing. Isn't it better to look forward rather than back? Approaching retirement, my pressing question is: what do I want to do next ?
After looking into some basic Zen philosophy, I think it also makes sense to consider focusing on spending more time in the present. The past and the future being ideas compared to the reality of the present - it's like watching a movie compared to real life. If the plight of the old is to reminisce, perhaps the plight of the young is to daydream. Both are important parts of life, but taking time to appreciate the present is easy to leave out.