Wow, just got back from doing 90 day check in Udon.
I brought nothing with me except my passport.
I only waited about five minutes, then handed officer my passport.
He said he had only Phuket address in computer and wanted to see my Udon address papers
I told him that I did not bring them. He asked where I lived in Udon, so I told him Pumpini Condos.
I did not even know my address or condo#.
Anyway, he went ahead and gave me my 90day stamp. He told me to bring paperwork next time.
Did not think anything could be so easy in Thailand. Shocking really.