August 9, 2025
2 min read
Analysis of cookie retention demonstrates two primary categories: session cookies and persistent cookies. Session cookies are designed for short-term data storage, such as authentication states or shopping cart contents, and are typically deleted when the user closes their browser window. However, browser-specific behaviors affect this duration; for example, Chrome’s session restoration feature can extend the lifespan of session cookies if a session is recovered after closure (Schaub et al., 2017)[^1].
Persistent cookies remain stored on the user's device beyond the current session. The retention period is determined by the Expires or Max-Age attribute set by the website. Empirical analysis indicates that persistent cookies may persist for periods ranging from several months to multiple years, depending on the domain’s configuration. For instance:
The actual retention time is subject to user intervention; deletion of cookies via browser settings or third-party tools overrides set expiration dates. Additionally, regulations such as GDPR and CCPA have prompted some services to implement shorter default retention periods.
Browser inspection tools provide granular visibility into individual cookie lifespans, allowing users and researchers to verify expiration dates and other attributes. Studies confirm significant inconsistency in cookie lifetimes across different sites and sectors (Matic et al., 2022)[^3]:
The findings highlight the importance of understanding both technical settings and evolving legal requirements for cookie retention.
