How far should a franchise go away from it's original formular?

[Jizz_Beard_thePirate]

Depends on whether or not the formula works and continues to work.

So like, if a game has a formula that worked in the past and made everyone fap and works today and continues to make everyone fap, there is zero reason to change to formula very much because it is a working formula that people love. Such as MK, Cod, Uncharted, Halo, etc

But if there is a formula that people once jizzed on but due to people's ability to be terrible at the game or that the times have just changed and there are better standards now that the formula just doesn't turn on many people anymore... Then the formula should be changed until it works once again.