In data-intensive real-time applications, such as smart transportation and
manufacturing, ensuring data freshness is essential, as using obsolete data can
lead to negative outcomes. Validity intervals serve as the standard means to
specify freshness requirements in real-time databases. In this paper, we bring
attention to significant drawbacks of validity intervals that have largely been
unnoticed and introduce a new definition of data freshness, while discussing
future research directions to address these limitations