Your brain doesn't have a cinematic memory of every moment. It's very malleable and memories will probably degrade more as you rely on this kind of thing more. Net effect may well be worthwhile, but it's definitely a downside to consider.
Every moment of your life is recorded in your mind with full perceptions and a time tag and is /potentially/ accessible.
Dianetics posits it's pain and unconsciousness that obscures memories, and if you contact and discharge them, memories return (http://www.dianetics.org).
Personally, I found this to be true. It's very interesting (and pleasurable) to recover a "forgotten" experience in a Dianetics session, which you can do by twinning up with another person that's read Dianetics, or by getting a free intro session at a local Scientology organization.
http://www.amazon.com/Dianetics-Modern-Science-Mental-Englis...