Long term memories aren't all of equivalent quality. More grounded recollections empower you to review an occasion, method, or reality on request—for instance, that Paris is the capital of France. Weaker recollections frequently ring a bell just through inciting or reminding.
Long term memory isn't static, either. You don't engrave a memory and abandon it as though untouched. Rather, you frequently amend the memory after some time—maybe by consolidating it with another memory or joining what others educate you regarding the memory. Thus, your recollections are