Full Answer

GA4's data retention setting controls how long event-level and user-level data stays available in Exploration reports. Standard (free) properties offer two options: 2 months or 14 months. The default is 2 months, and many store owners never change it — so their custom funnels and segments lose data silently after just eight weeks.

This does not affect the pre-built standard reports in the Reports section. Those use aggregated data that Google retains indefinitely. The gap catches people when they build an Exploration to compare this December's checkout funnel to last December's — the older half simply isn't there, and GA4 renders the chart anyway with no error or warning. The result is a comparison that looks complete but is quietly hollow.

The practical fix for any WooCommerce store running GA4 is to enable BigQuery export. Once linked, GA4 streams raw event data to BigQuery daily at no retention limit — your purchase, add-to-cart, and begin-checkout events stay queryable for years. For most small stores the BigQuery cost sits under five dollars per month. The key is setting the export up before you need the data, because GA4 does not backfill events from before the link was created. A detailed walkthrough of the setup and cost math is covered in GA4's 14-Month Wall.