I have recently been convinced to use the 195 degree T-stat.
If an engine runs too cold, the fuel/air mixture can separate & allow raw (condensed) fuel into the cylinders. This leads to cylinder wall "washing".
The protective oil coating on the cylinder walls, gets diluted & rinsed away by the solvent action of the gasoline.
This all causes premature engine/ring/cylinder wall wear.
This is also why it's good to warm an engine up for a few minutes, even in a hot climate such as Florida.
Just got back from Boca Raton yesterday. It is damn hot down there!
Nice beaches though.