I can strongly recommend to apply as early as possible, as Tod advised 30 days for Udon Thani. 30 days will include day of application and your last permitted to stay day. In case of any problem / paperwork needed in addition, you will have time to do this.
I do some safe work right after that story with affidavits happened. I have income from abroad, and instead of withdrawal from foreign ATM card, I start to do transfers to bank account, ensure they shown as FFT. And also keep watching affidavits situation. Even if my Embassy still issue them, the changes can be at any moment. Not happy with idea to keep 400k on account.
Also, if you working legally and done at least one yearly tax 91 form, you can do extension based on working. But more paperwork needed :(
maybe require next day. My TM30 by mail perfectly accepted and slip returned. I now at hotel in province and manager asked me for passport, but I not take it with me to travel upcountry. Will try to re register later online or by mail
Tod, actually possible to buy single reentry as many times as need. One year I done this 3 times as my traveling was absolutely unexpected and not planned. This will cost space in passport, if someone concerned about space and empty pages. Economically multiple reentry become effective if travel 4+ times per year extension. And as hassle free of course one multiple per year extension is best in term of no think about reentry and save passport empty pages.
Gary Sparkes you can get reentry permit at any time. Due to long queues at immigration much easier to get it at airport if such service available. For last 3 years I get all my reentry at Suvarnabhumi exit 2, at reentry counter. If you don’t mind extra money then get multiple. But you can get it ONLY before your flight and not in advance. Will need to provide boarding pass, all other services done by girls at reentry counter. They have small fee on top like 200 THB. Be wise to plan time and arrive as early as possible, I once spent 40 min at reentry counter
Doron Azulay Better to keep your 400k on time deposit. This will give you some income interest, not much but enough to compensate currency fluctuation rates, and no any ATM card need at all (secure + ATM cost money every year). I kept on time deposit account and no problem with acceptance at immigration.
The same confused thing discussed with friend and get a solution: Prepare papers to be sent by post and send them from airport. Post office will stamp it current date: but I not remember if any post office in CM airport, in both BKK airports post offices open 24 hrs no holidays