Maximum Taxation
First of all we will look at the money side of the fief. As we all have seen money , there is never enough money. As a result one needs to better manage their fiefs.
The maximum amount one can tax a fief without drops in loyalty is 20% (15% after the plague). Thus this is the goal of every noble who wants money. One can raise the tax above 20% but as the tax raises above 20% so does the chance of sudden rebellion .