Ask HN: Consciousness thought experiment-Is memory capacity of brain bounded?

There are people who can remember pretty much every day of their lives in great detail; this phenomenon suggests our brains are capable of much more than we usually use in a lifetime. But, as a thought experiment, suppose such a person lives forever. At what point (if ever) would he or she experience a marked decrease in memory function? If it happens, would it be sudden or gradual? To me this suggests an approach to a meaningful exploration of where consciousness resides. If it resides solely in our brains, then there should be hard physical limits to memory. But if consciousness is space-time distributed, and the universe is possibly infinite, then memory may well be infinite.