I have fished bass tourney's nation wide going on 30 years now. I subscribe to the practice of changing trailer tires and boat batteries every two years regardless of how they look. In my opinion, both are ****! I have not found it to be worth it to spend the extra money for extra tire life. the Goodyear Marathon was one of the most OEM bass boat tires out there, and I have NEVER seen a worn out marathon; they always fail before the tread life has expired.
Despite all of that we had a high speed blow out 20 miles into our OK to New England trip in 2016 with OEM D rated tires. Replaced with a set of E's and they are about to make their last big trip.