The government has said that it intends to raise the pension age if life expectancy keeps increasing, so the sky could be the limit in theory!

BBC: Fergus Muirhead

In theory, a discretionary central bank could limit the quantity of money and achieve long-run price stability by controlling the growth of nominal final demand.

FORBES: The Federal Reserve's Flawed Approach To Monetary Policy

Another theory is that Apple may have reached a theoretical limit to how many products can be produced in a specific window of time.

WSJ: New iPhone Sellout Tests Apple Supply