I normally apply for mine 6 weeks before the expiration date in Chiang Mai, if I’m going to be away when it’s due I let them know and apply for renewal on return
Just received my yearly vis, but I am on a type O retirement visa, had to get letter from Bangkok bank head office listing all transfers in, a statement saying they were international transfers, they then copied every page of my bank book, cost 209 baht, 7 days later went back received documents, paid another 100 baht, and visa issued at Chiangmai immigration immediately, hope this helps