When do I pay Capital Gains Tax When Scaling 1031 Exchange?

[Austin Carter]

So quick question I couldn't find while searching the forums. Let's say you hoise hack and 1031 your way up to multiple properties and you finally use one of the homes as your exclusive principal residence and sell. How many of the properties do you pay capital gains tax on? I'm aware of the section 121 exclusion but am curious about how the deferred capital gains are paid when scaling multiple properties?