Clean Code: DRY, KISS, and YAGNI Rules

Every piece of knowledge must have a single, unambiguous representation within a system. Avoid duplicate validation logic or constant definitions. If a rule changes, you should only have to update it in one place.

Systems work best when they are kept simple rather than made complex. Avoid premature abstractions, clever one-line hacks that are hard to read, or complex libraries when a few simple functions are sufficient.

Never program features based on expected future requirements. Build what is needed today, structuring code to be easy to modify when future needs actually arise.