The order changes based on where the inputs and outputs are located on the gateway so in the end it comes down to finding a condition match, regardless of the order they are in. You want to make your conditions unique enough that the order wouldn’t matter. It will only follow the default if none of the other conditions find a match. The thing you want to think about when setting a default is, is this really where I want the process to flow to when none of the others match or one might say when all of the conditions fail.. An example would be the default path next activity might be to an email, so the question would be, do I want the email to be sent if none match/all fail, or maybe I’d prefer to set the condition for when that email should be sent and change the default to a different path.

I like to think of the default gateway as the freebie. Set everything else that is NOT the default. 

Thanks everyone for the replies.  They really helped!