Before you launch a test, find out how many visitors each variant needs to detect the lift you care about — and roughly how long that takes at your traffic. Stops you from calling a test too early.
Visitors needed per variant
8,158
16,316 total · detecting 5% → 6.00%
≈ 3.3 weeks to reach significance
at 5,000 visitors/week across both variants
Smaller lifts need dramatically more traffic. Run the test the full planned duration (ideally whole weeks, to cover weekday/weekend patterns) — don't stop the moment it looks significant.