Many Thai people don't live at the address on their HB, it's not important.
Yes, it's easy to change YHB, the only difference to the BHB is that you need a letter from the old town house.
In 25 years, I was never asked for YB at immigration, they don't care about this.
I only changed my YB as it was easier to apply for citizenship in Bkk. My BHB is still there, despite living outside Bkk. I'm in no hurry to change it.