Exactly, so why not stick with what you know, that is, what you've used with FW15, 16, 17 etc ?
If I normally used, lets say a Matrix 2x12 FRFR when I play my Axe, and that is what I was using with fw 17.04, it seems like it would make no sense to install FW18 and grab a set of headphones, just as it wouldn't make sense to throw some new pups into the guitar first etc.
When I try out a new FW I use the same monitoring, use the same guitars, with the same pickups, etc. I want to keep everything the same so any tonal changes can be attributed to the new FW, not a different monitor etc. Shouldn't matter what you use, as long its what you normally use.