So, the game says that a "normal" tax rate is 10%, but I've never run a region at only 10% tax. While you can leave a region at 10% and it will literally never have any issues, you're essentially wasting free gold.
I've found you can run a 14-15% tax rate in most places without any additional problems.
You can run an even higher tax rate of 17-19% depending upon region location, and still only have to occasionally hold courts as far as I am aware.
Meanwhile, pushing your region over 20% I've seen as fairly common as long as you are willing to hold regular (or daily) court sessions.
So, I'm curious as to what people consider a "Normal" tax rate, and what you run your own regions at and for what reasons.