Lost Revenue Recovery Flows

Hello, 

I am an Email Marketer in training and i have really found the community posts on here very very helpful. Just wanted to start by saying thank you guys so much for having your conversations and asking the questions!

I am currently setting up Abandoned series emails based on the flow triggers ive seen, i wanted to ask if anyone knew the following:

For the following Flows, should the initial trigger occur “At least once” or “Zero Times”

Abandoned Checkout:

Abandoned Browse:

Thank you for the help