From what I've heard, prices of new builds keep going up, especially in Bangkok, prices of anything more than a few years old go down. Meaning lots of negative equity.
I did it myself last year in Chiang Mai. I'm a UK citizen so it may differ according to your nationality. This is my recollection of the steps (again, as it applies to a UK citizen at Chiang Mai immigration).
1. Enter Thailand on tourist visa or visa exemption
2. Deposit 800K THB in your bank account (for CM, this only needs to be in your bank account when you do step 3 - there's no seasoning time at CM immigration for the non-o visa). BUT note: for Step 6, it needs to have been in your account for 2 months.
3. Go to immigration and complete form for converting to a non-o visa (you must have at least 21 days left on your permitted stay. Costs 2000 THB.
4. You'll get an "under consideration" stamp in your passport, with a date to return to immigration.
5. Return to CM immigration on that date. You'll get a non-o visa stamped into your passport, with a new 90 day stay stamp.
6. When there are less than 45 days on your stay stamp, AND your 800k has been in your bank account for 2 months, go back to CM immigration and apply for a one year extension to your stay. You'll get that stamped in on the same day. That gives you a new one year stay stamp. Costs 1900 THB.
Regarding the 800k, yes, it needs to be in your bank account before you apply to convert your tourist visa / visa exemption to a Non-O. But just a day is fine. But it needs to have been in your bank account for 2 months before you apply for your one year extension.
Visa agencies are great for people who are too busy / too lazy to do the research needed, people who don't like queuing and people who struggle to organise paperwork.
Other option is to come to Thailand on a tourist visa, convert it to a non-o visa while inside Thailand, then get a one year extension based on retirement. No insurance requirement.
However, you need to have 800,000 Thai Baht in the bank account. But there are visa agencies that may be able to get around this requirement for a fee.
No. At Chiang Mai you need the 800k in your bank account when you apply for the initial Non-O, but there's no seasoning period. It could have been deposited in your account the day before you apply for the Non-O. At Chiang Mai the 2 month seasoning only applies to the application for a one year extension.