@Michael *******
, just so we're clear. Getting that O-A visa from a thai consulate in your country BEFORE you come here is far superior to getting a 90 day Non-O visa and then a yearly extension of stay <- which is what you really get INSIDE the country even though it's called a "retirement visa" :/ .
You can do it all from your country and when you show up with that visa in your passport you will be stamped in for a whole year. The visa is unlimited entry/exit for the validity of it (a year from the date it's issued) and every entry to the country gets you stamped in for a whole new year.
Exiting and re-entering just before the visa expires gets you stamped in for another year (giving you two years of stay out of a visa that's valid for a year)
There's no comparison between what you can get in country and an O-A you get in your country before you come here.
Good Luck (y)