Setting up a new GA4 property takes 10 minutes. Setting it up correctly takes considerably longer — and the gaps between “working” and “correct” show up months later as bad data, missing attribution, and incorrect conversion counts. This checklist covers 15 settings that most teams skip during setup but that cause real data quality problems down the line.

1. Reporting Time Zone and Currency

Admin → Property Settings. Set your reporting time zone to where your business operates — not UTC. Mismatched zones cause “today” to include the wrong hours. Currency should match your transaction currency. This cannot be changed retroactively without impacting historical comparisons.

2. Data Retention Set to 14 Months

Admin → Data Settings → Data Retention → change from 2 months to 14 months. The 2-month default limits Explorations to 60-day lookbacks. 14 months enables year-over-year comparisons in Explorations.

3. Internal Traffic Filter Set to Active

Admin → Data Filters. After defining internal traffic IP ranges, the filter defaults to “Testing” mode. Switch to “Active” to actually exclude internal traffic — the single most commonly missed step.

4. Mark Key Events as Conversions

Admin → Events → toggle “Mark as conversion” for your key events. GA4 doesn’t auto-track conversions. Mark: purchase, generate_lead, sign_up, contact_form_submit, book_appointment — whatever defines success for your business.

5. Unwanted Referrals: Payment Processors

Admin → Data Streams → More Tagging Settings → List Unwanted Referrals. Add payment processor domains: paypal.com, stripe.com, checkout.yourpsp.com. Without this, checkout sessions get attributed to “paypal / referral” instead of the original paid or organic source.

6–10: Additional Critical Settings

• 6. Cross-Domain Measurement: configure if you have multiple domains (main site + checkout subdomain) to prevent new sessions on each domain hop
• 7. Google Signals Off Unless Needed: enabling causes data thresholding — rows suppressed for segments under ~50 users. Disable unless cross-device reporting at scale is essential
• 8. Industry Category: Admin → Property Settings → unlocks benchmarking data to compare metrics against industry peers
• 9. Audiences for Remarketing: create key audiences immediately — they only collect members from creation date forward, no backfill
• 10. BigQuery Export Enabled: Admin → BigQuery Links → enable daily export before you need historical data you cannot later retrieve

11–15: Integration and Access Settings

• 11. Google Ads Link: required for conversion import and audience sharing for remarketing
• 12. Search Console Integration: Admin → Search Console Links → connects organic search query data to GA4 landing pages
• 13. Custom Channel Groups: build groupings matching your business — brand vs non-brand paid, newsletter vs promo email
• 14. Enhanced Measurement Review: scroll tracking defaults to 90% (too high for most content); file download tracking may miss your actual file types
• 15. User Roles: Admin → Access Management → add team with appropriate roles; Analyst for most, Editor for tag managers only

Related: GA4 Internal Traffic Filtering, GA4 Channel Grouping.