Hi @Nermine, glad to see you back here in the community.

The “has not been in this flow” Filter rule means that before any person enters the Flow, it has to satisfy that rule that they haven’t been in (the current) “Added to Cart” Flow before.

Since this is a Metric Triggered Flow based on what I see as the “Added to Cart” event, users can go into these Flows unlimited times - unlike List or Segment Triggered Flows where they can go through it exactly once.  In other words, every single time a returning subscriber adds something to their cart, including subsequent “Adds to Cart”- this Flow Filter is evaluated to determine eligibility to go through the Flow.

You can adjust the days to how frequently you want people to be getting these emails from your Flow.  If you have it at 14 days, that means at most, they can only go into this Flow once every 14 days (max).  This also prevents people from going through this Flow more than once in the same visit if they add a second or more items to their cart because remember, EACH time they Add to Cart, you are sending an event to Klaviyo.  If you didn’t have this Filter, and someone adds 3 items to their cart, they will go through your Flow 3 separate times (one for each item) and get tons of seemingly similar emails.  This of course is probably a bad user experience and risk people either unsubscribing or possibly reporting it as Spam.

I think 14 days is a safe window of time to start, but I’ve seen it as short as 1 or 2 days, to as long as 30 days.  It really depends on how aggressive you want these Flows to activate and the volume of other emails that your audience might be receiving, your deliverability status, and the level of engagement of your audience.  

As a side note, during BFCM (which is right around the corner at the time of this posting), you may want to be more aggressive since you may have a higher than usual returning subscribers and you want to make sure they get this email each time during BFCM (or holiday period).  But, if you have poor deliverability or concerned about the volume of email, or you think other emails or Flows are more compelling, then you should adjust accordingly.  There’s not really a one size fit all answer, but if I had to pick, 14 days (as Klaviyo defaults to), is probably a safe bet.

Hope that helps!

Joseph Hsieh // retentioncommerce.com // twitter: @retenion  

Thank you so much for the detailed answer that was really helpful.