GA4 Property Setup Checklist for Marketers
A GA4 admin checklist for marketers: data retention, internal traffic, unwanted referrals, cross-domain and Google signals settings.
Spend 20 minutes in GA4 Admin before you trust any report: set data retention to 14 months, filter internal traffic, list unwanted referrals and set up cross-domain measurement if you send visitors to other domains. None of these fix past data except retention, so do them on day one.
- Data retention for standard properties is 2 or 14 months. Pick 14; it affects explorations and funnels, not standard reports.
- Internal traffic is defined in tag settings, then filtered with a data filter you test before activating.
- Unwanted referrals stop payment providers or login domains stealing credit from the real source.
- Cross-domain measurement keeps one session across domains you own.
- Keep Admin changes in a shared change log so report shifts can be explained later.
Checked 4 November 2026 (CET) against Google Analytics Help and Google developer documentation. GA4 menus and limits change, so confirm in your own property. "Our view" marks MentionX opinion. Ledgerline is a fictional company used for illustration.
01The checklist
| Setting | Where | What to set |
|---|---|---|
| Data retention | Admin → Data collection and modification → Data retention | 14 months (standard). 360 adds 26, 38 and 50 months. |
| Internal traffic | Admin → Data streams → (web stream) → Configure tag settings → Define internal traffic | Your office and VPN IP ranges |
| Data filter | Admin → Data filters | Activate Internal Traffic after testing |
| Unwanted referrals | Tag settings → List unwanted referrals | Payment, booking or SSO domains |
| Cross-domain | Tag settings → Configure your domains | Every domain you own that a visitor passes through |
| Enhanced measurement | Data stream settings | Confirm which automatic events are on (lesson 3) |
| Key events | Admin → Events | Flag the actions that matter (lesson 4) |
| Links | Admin → Product links | Search Console and Google Ads (lesson 15) |
02Data retention: why it matters
Google's help page is explicit: the retention setting does not affect standard aggregated reports, only explorations and funnel reports. If retention is 2 months and you build an exploration for the last quarter, the older weeks are missing. Increasing retention applies to data already collected; reducing it deletes the affected data in the next monthly process. Large and XL properties are limited to 2 months.
03Internal traffic, tested safely
Filters start in a testing state. Leave the Internal Traffic filter in Testing for a few days, then compare the Test data filter name dimension in an exploration against normal traffic. Only activate once you see it catching the right rows, because active filters permanently exclude data.
04Unwanted referrals and cross-domain
If customers pay on a processor's domain and return to a thank-you page, GA4 may start a new session credited to that processor. Add those domains as unwanted referrals. If your blog and app live on different domains you own, use cross-domain measurement instead, so one visit stays one session.
Our view: a property with tidy settings and three key events beats a sprawling one. Resist adding settings you can't explain to a new team member.
Next: Events and enhanced measurement. Or return to the GA4 for Marketers track.
05Common questions
What data retention should I choose in GA4? On a standard property, choose 14 months, the longest option. The setting only affects explorations and funnel reports, but the default 2 months leaves little history to explore.
Does changing data retention apply to old data? Increasing retention applies to data you have already collected. Reducing it deletes affected data in Google's next monthly process.
How do I exclude my own team's visits? Define internal traffic by IP address in the data stream's tag settings, then activate the Internal Traffic data filter in Admin. Test it first; filters affect data going forward.
Questions people ask
3 answersWhat data retention should I choose in GA4?
+
On a standard property, choose 14 months, the longest option. The setting only affects explorations and funnel reports, but the default 2 months leaves little history to explore.
Does changing data retention apply to old data?
+
Increasing retention applies to data you have already collected. Reducing it deletes affected data in Google's next monthly process.
How do I exclude my own team's visits?
+
Define internal traffic by IP address in the data stream's tag settings, then activate the Internal Traffic data filter in Admin. Test it first; filters affect data going forward.
Sources
- Google Analytics Help, Data retentionsupport.google.com
- Google Analytics Help, Filter out internal trafficsupport.google.com
- Google Analytics Help, Identify unwanted referralssupport.google.com
- Google Analytics Help, Set up cross-domain measurementsupport.google.com
- All accessed 4 Nov 2026.