Design system contribution forms usually ask for accessibility notes and API sketches. They rarely ask “how many kilobytes does this add on a cold path?” That omission is how date-pickers grow into silent regressions.
We coach teams to add three fields to every RFC: estimated gzipped weight of new dependencies, whether the component loads on critical journeys, and an owner for the budget exception if one is needed. Review forums then reject or defer proposals that blow the foundation budget without a documented trade.
The first month feels pedantic. The third month, product squads stop proposing one-off icon fonts because the checklist made the cost visible. That is design system governance doing its job — not a separate “performance initiative” that dies after the audit slide deck.