Selected thinking
Design systems that actually help products ship
A practical way to build shared interface rules without turning the system itself into the product.
Design systems are useful when they remove recurring decisions. They become expensive when maintaining the system starts to matter more than improving the product.
Begin with repetition
Do not start with an inventory of every component you might one day need. Start with patterns that already repeat: typography, spacing, controls, feedback, navigation, and surfaces. A repeated problem earns a shared solution.
Write down the decision
A component without a reason is just a reusable shape. Document when a pattern should be used, what it communicates, and where it should not appear. Those constraints are what make the library a system.
Keep the feedback loop short
The system should evolve beside production work. Changes need to be tested in a real feature, not only in an isolated component gallery. If a rule repeatedly needs exceptions, the rule is probably wrong.
The best measure is mundane: designers make fewer avoidable decisions, developers write less duplicate code, and users encounter fewer surprises.