Two Rules of Thirds

Rule #1

The game was developed by the same Firaxis Games team that developed the expansions on Civilization V, and most of the new mechanics introduced in these were present in Civilization VI at its launch.^[10] This follows from Sid Meier’s “33/33/33” rule of sequel design: 33% of the game should retain established systems, 33% should feature improved systems over the previous version, and the remaining 33% should feature new material

Wikipedia: Civilization VI

Rule #2

When training for something, you should be disappointed in your results a third of the time, content with them a third of the time, and pleased with them a third of the time.

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What both of these ideas get at is change. Grow or die.

How much change? Well that depends, but the rule of thirds feels like a good proxy. It’s not going to be exactly one-third, but it’s the right approach. Sometimes we should be disappointed in a result and sometimes we need to change a major thing. But sometimes we’ll be pleased and sometimes we need to keep what works.