There is never too many, but if you want a number: the moment you see the theater going bankrupt then you're getting close but not there yet.
It's when they need a new truckload of corn that you might possibly think about the fact that you're almost having too many popcorn. It's only when the stuff is depressed, begging you to stop and even trying to bribe you into stopping; then when they bribe you with enough money that you might consider stopping eating popcorn.
How do I seize power and control of the Forum?
Just asking for a friend