Changing just rear tires for higher load rated tires?

I agree that if you have no need to change the tires if everything is working for you. My trailer, at 6,500 lbs. is considerably below the tow rating of my Tundra and I also agree that I would never tow on a regular basis anything approaching the 10K tow rating. I'm simply stating that each situation i.e. specific vehicle, tires and trailer being towed can make a difference on whether P tires are OK or LT tires would be better.