Is there any consensus on wether or not it will increase drive life if you swap outdrives seasonally to allow for even wear on Bravo 1 XR's

You'll find differing opinions.

My opinion is that while you have the drive off the boat, pull the back cap and inspect the gears for pitting or smearing. Also take a dial indicator and check the back lash for both fwd and reverse gears.

Then pull the top cap and look at the needles. Pull the top gear and inspect the pinion.

If she looks nice, THEN swap them and go back on the boat.