Santiago has been the marketer and site manager for FixMyCar.com for the past 15 years. He and the developer team have spent much effort improving the user enjoyment of the site. Recently, performance metrics are showing the speed of the site has regressed significantly over time. Which long-term maintenance program can help by limiting certain metrics that affect performance?

Performance budget is correct because it sets limits on key site performance metrics, such as load time and responsiveness, to ensure that FixMyCar.com maintains a high-quality user experience over time. By establishing a performance budget, Santiago and the developer team can prevent regression in site speed and other critical metrics, helping sustain usability and conversions.