system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Is there an expiration to the memory stored in our brain? Do memories get completely "lost" if remained un-recalled for certain period of time?
gpt
There is no definite answer.

When you remember something, it's much less that you are remembering the actual event, and more likely you are remembering you remembering it. Kind of like a picture of a picture. This is why you tend to remember very specific things after a long time. When remembering a party, you remember a few specific details (a person, a place, an activity) but you don't remember everything.

So it would depend on how often you remember something. And how often you remember it might destroy some details.

But aside from that, there is also Alzheimer's, a degenerative disorder where connections in the brain start to not work due to tangles and plaque build up in the brain.

As for if there is an actual limit on how long a memory is stored before the brain says "he doesn't need this anymore, chuck it". We don't know.

There are many elderly people who can remember their childhood with great detail. Leading to a conclusion of "no", but at the same time, they might remember these memories often, and therefore keep bringing them back up to the top of the pile.