Hi @CDugan2
It kinda depends on what the workflow is doing and what you are trying to do.
Strictly speaking anything that converts a contact, means that contact will then exist in the system.
Something simple could be a list of contacts with a create date less than 24h ago - we could call them new. So if you are on that list we treat you differently.
Depending on your use case(s) it might be easier to classify and segment based on existing customers, then use list membership as part of your if/then filter.
I hope that helps.
Frank