Interestingly, I think that keeping everything can actually give us a much more fuller account of our lives. If were are able to create an AI that will help with the augmentation of all the data. I can really see something like: http://www.imdb.com/title/tt2290780/?ref_=ttep_ep1
Which is what Gordon Bell (http://en.wikipedia.org/wiki/MyLifeBits) and Microsoft Research have been looking into.