It really depends on the kind of popup and trigger you set:

– If you create a popup with an “exit intent” trigger, you should set “1” page view minimum because you want to give the opportunity to every visitor leaving your website to ask for a reminder.

– If you create a button widget (little button on the bottom left or right of the page) or an accordion popup, you can put it on every page from the first page view to the last one. This gives the opportunity to your visitor to click on it at any time without bothering him during his visit.