The memories of most humans are constantly changing. The proper metaphor for memory is not a printed book. It is more like a website that is constantly being added to and edited, often with old irrelevant bits being deleted.
People do not actually remember every detail of their lives. They know an overall narrative, the setting, and the characters. When reminded of a specific event, they reconstruct the memory from those bits like a theater company creating a scene from a play.
Updating memories based on the facts you observe in the world is a proper and healthy thing to do, because human memory is much less reliable than observation of the facts of the world. If your memory disagrees with the facts, then the thing at fault is probably your memory. But this process can be used too often, and manipulated. People construct their memories to fit the narratives of their life. Often, memories are constructed or edited to fit in with social norms.
For example, if you ask people in a survey about their level of education, reported education levels are much higher than the actual education rates of the time period. This is not due to the lesser educated people dying off, and we do not think that people are deliberately lying. People seem to make honest mistakes, updating memories about the facts of their lives to match current conditions. Consider someone had a couple years of college in the 50's, and then got a good job. Nowadays, people know that it is impossible to get such a job without a full four-year degree. The person being interviewed knows that he went to college, knows that he got a job that requires a college degree, concludes that he must have received a college degree, and therefore remembers that he has one.
Similarly, very few people will report voting for a politician that turned out to be bad. They know that they would not vote for him today, and so they conclude that they must not have voted for him in the past.
I have one memory that I know to be a false reconstruction. There is an important scene in Lord of the Rings where Frodo offers the One Ring to Galadriel, and she responds by describing what she would be become if she took the ring. In the book, she says she would become "as beautiful and terrible as the morning and the night". In the movie, this was changed to "beautiful and terrible as the dawn."
I remember watching the movie and seeing Galadriel say "the morning and the night". I remember her face and the intonation of her voice as she said it. But she never said it. My brain reconstructed the dialogue based on the text of the book, filling in the face and voice. Watching the movie again did not erase this memory. It simply created a new memory of her saying 'the dawn'. I have both memories, as if I watched two different cuts of the movie.
In general, however, my mind does not do this nearly as much as most people. My brain usually does not reconstruct memories. This means that the memories I have tend to be more accurate than the memories of most people, but I have a lot fewer of them.
I have very few memories of my childhood, even relatively recent events. Almost all of elementary school and middle school is simply gone. It was a big surprise to me when I realized that most normal people remember the names of most of their elementary school teachers. The only reason I know any of their names is that I remember my parents talking about them, years later.
'Blur' would be the wrong word; the memories are simply gone or were never formed. I remember just a few events from each year, at most. Even vast sections of my recent life are lost to me. I kept random notes of various things when I worked at a lab supply company before going to grad school. As I was looking through some of these recently, I read several descriptions of events that I have no memory of now. They were important events at the time, involving miscommunication, mistakes, office politics, and other high drama, but they are completely gone from my memory. It is like reading an account of someone else's life. I think that most people's minds would reconstruct a memory based on the description and memories of the people involved, but mine does not.
I am far more likely than most people to respond to a question about my life with "I don't know." or "I don't remember." This often surprises my friends and family. It seems especially surprising when asked about my desires or preferences. My friend recently asked me if I liked a brand of cider more than a different brand I had drunk last week. I could not answer the question, because I did not have a sufficiently detailed memory of the last week's cider. They were both simply 'good' and any comparison was impossible because my memory did not have the detail needed to support one. I think that most people would have reconstructed a memory in order to make the comparison, but my brain does not work like that.
My brain simply does not see fit to record most of the things that happen to me, and does not reconstruct memories about them when prompted. Instead, it remembers scientific and historical facts and constructs theories and connections about those facts when prompted. I would not want to have the memory system of a normal person. But I suspect that most normal people would not want to have my memory system.