Many people learn too late that GA4 doesn't keep detailed data forever. After a set period it disappears from some analyses. Here's what that means and how to secure a longer history.
What data retention is
Data retention is the period GA4 keeps user- and event-level detail usable for some analyses. It's usually set to 2 or 14 months. After it expires, this detailed data is removed.
What it applies to and what it doesn't
- It applies mainly to detailed, ad-hoc analyses (e.g. Explorations) that work with user-/event-level detail.
- Standard aggregated reports beyond the retention period usually remain available because they're pre-aggregated.
Always verify the exact scope in current GA4 documentation — Google adjusts settings and behavior.
How to secure a longer history
- Set retention to the longer option (typically 14 months), unless you need it shorter for a retention policy.
- Export data to BigQuery. Raw data in BigQuery isn't subject to GA4 interface retention — you hold the history. See GA4 BigQuery export.
Relation to server-side
Retention is about keeping data; server-side tracking is about the data being complete and reliable in the first place (fewer losses to ad-blockers and ITP). One without the other isn't enough — you want complete data and to keep it long enough.
Summary
Data retention in GA4 is how long detailed data stays available (2 or 14 months). You secure a longer history by setting 14 months and, above all, exporting to BigQuery. Verify current details in GA4 documentation.