My annual extension of stay date is 15 March. So last year, I renewed on 3rd Feb (within the 45 days in advance window). However, the mistake I made was that, after renewal, Krungsri told me of a better rate of interest on the fixed deposit, so I changed to that better FD. Ho, ho, ho! This year, at renewal time, the IO was not happy, although after much persuasion her superior agreed and granted me the extension. So don't tamper with the fixed deposit - now Krungsri offered me 2.2% but I can't take up that offer - for 2 months after the renewal has been done.