I think its kind of silly that nomads have to retake the razing decision every 5 years rather than all at once. It doesn't take several decades to pillage a city into ruins, and historically the Mongols did do that to Xia and parts of Khwarazmia.

I took a look at the game files and couldn't figure out a way to do it though. The best I could find was the define for the wait time, where you can set it to 0 years in which case you can do it once a day. Has anyone looked into it to find if it's possible and I'm just missing how?