Can popups be used to build an email list on Shopify?

The optimal frequency for displaying popups on a Shopify store is once per session, ideally after a visitor has engaged with your site, for instance, if the visitor has spent 30-60 seconds or scrolled 50-70% of the page. This balances visibility without annoying shoppers. For returning visitors, space out popups, and show them weekly or after a few visits. You should also test timing to see what works best for your audience since overly aggressive popups hurt conversions.