It promotes legitimacy.

Finally, while courts are always free to overturn their own precedents and so adapt to changing factual circumstances on their own initiative, sunsets can serve an anti-inertial function. Some issues may, for a variety of reasons, demand periodic revisitation to maintain judicial legitimacy. Sunsets offer a formalized mechanism for ensuring such revisitation occurs. Other doctrines—particularly fact-tracing and fact-modifying rules— seemingly demand recalibration to ensure that the doctrinal outcomes continue to track the underlying purposes of the rule. Again, sunsets would provide an explicit structure enabling such adjustments to regularly occur.