GA4's default retention throws away your data in two months

GA4 has a data retention setting for event-level data. The default is two months. The maximum on the free tier is fourteen.

Aggregated reports are unaffected — standard reports still show longer periods. What expires is the granular, event-level data used by explorations, custom segments, and any analysis where you want to slice by something the standard reports do not offer.

Why this catches people

The default sounds like a technical detail and behaves like a permanent decision. Change it today and it applies going forward, not backward. The two-month-old detail you needed is gone before the setting is even found.

Nothing warns you. The reports still work. Only when someone builds an exploration covering last year do they discover it returns nothing for most of the window.

What to do

Set it to fourteen months on every property, on the day the property is created. There is no downside, no cost, and no reason for it to be anything else.

If you inherit a property, check it first. It is one of about four settings worth verifying before doing any analysis at all — alongside the timezone, the currency, and whether internal traffic is being filtered.

The bigger point

Fourteen months has the same problem as Search Console's sixteen: it is not enough for a genuine year-on-year comparison with room to spare, and the shortfall is invisible until the moment you need it.

If a period matters to you — a peak season, a migration, a campaign you will be asked about in two years — the only reliable approach is to extract what you need while it exists and store it somewhere you control.

That sounds like over-engineering right up to the first time someone asks how this Christmas compared to the one before last, and the honest answer is that nobody knows any more.

The checklist for a new property

• Data retention: 14 months.
• Timezone and currency: correct, and never changed afterwards.
• Internal traffic filter: defined and activated — defining it does nothing on its own.
• Unwanted referrals: payment and booking domains listed.
• Key events: the standard vocabulary, with values.

Five minutes at creation, and none of them can be fixed retrospectively.