Our everyday experience tells us that everything has a limit, including our memory. It is likely that there is a limit in our memory, although there is no one on earth who has reached its limit.
There is no need to be frugal with your memory, worrying that you may exhaust your memory space.
As a matter of fact, the more you use our memory to store and recall, the more efficient it is at doing them. The less you use your memory, the less efficient it is.