Testing remains a core pillar of paid search success. Experienced managers treat each campaign as a testing ground to discover what resonates most with their audience. From experimenting with different headlines and descriptions to testing callout extensions and sitelinks, every variable is an opportunity for growth. Multivariate testing helps assess multiple elements at once, while A/B testing isolates performance factors. Managers review statistical significance before implementing broader changes, ensuring test results are reliable. They also rotate creatives based on engagement history to avoid ad fatigue. Ongoing testing builds a feedback loop that refines not only the campaign but also the broader messaging strategy.