Chesterton's Fence
Understand the original purpose before altering a system.
Explanation
Before changing or removing any existing system, rule, or process, first make sure you understand why it was created in the first place. Writer G.K. Chesterton pointed out that things that seem pointless or outdated usually exist because they solved a problem that you might not be aware of. People who don't understand this history often end up recreating the same problems.
Real-World Example
Developer: 'This validation check is useless, removing it.' Month later: database corrupted. The check prevented bad data from an integration they didn't know about. Company removes 'pointless' approval process. Result: fraud spike. The process was preventing embezzlement. Society abandons tradition. Discovers tradition solved problems they forgot existed.
How to Apply
Before changing anything, ask: Who put this here? What problem did it solve? Is that problem still relevant? What might break if I remove this? Talk to people who were there when it was created. Document why things exist. When you add something, document why—be kind to future Chesterton.