I lowered mine to 10 from 15 and got the ride softer. Makes a difference.
X2. I recently drained and swapped my rims around to get maximum track width. Filled with water and set to 14psi per manual. It's too much pressure so I'll have to lower it.
Here is the test I use, set the tractor on concrete or similar, take the implement off the tractor or lower the implement to the ground so all the weight is off the tractor, lower the air pressure until the entire tread on the bottom part of the tire is touching the ground. Check the pressure and let out probably 1psi more and it should be good to go. This is for maximum traction.
I recommend this for rear tires only. As most front tires, like mine with the loader, need more psi so they don't get pinch flats when you get the loader full of material.
Just noticed the manual says 36psi for the fronts, but on the sidewall they say max load at 52psi. I also recommend going by what the tire says on the sidewall over the owners manual, and that's for trucks, trailers, ATV's and more.
