Hua Hin Immigration told me today that one can extend your one-year (some call it "retirement") visa only within the 30-day time period before it expires; however, after some cajoling, I was advised that it can be done earlier but for an extra charge (5,000 baht!).
I was between a rock and hard place. My visa expires May 27th but I'm scheduled to fly back to the states on April 26th. I ended up with two choices: (1) Get it extended by paying an extra 5,000 baht (in addition to the 1,900 baht to extend the visa and the 1,000 re-entry permit)or (2) Just let the damn thing lapse, obtain a new Non-Imm O Visa this summer and then get a new retirement visa in the fall. Since I use a visa service in the states, the new Non-Imm O would have cost me about 3,000 baht in total and, of course, the cost of the one year visa is 1,900 baht.
Bottom-line, get it all done today and pay a total of 7,900 baht or wait and get it done for a total of 4,900 baht. While I could have saved 3,000 baht, I elected to pony up today and save myself the hassle of getting the two new visas in the future.
Moral of the story, I suppose, is to be aware that the cheap way to extend your one-year visa is to do it within 30 days of its expiration date. Next year, I'll stay until May (as you might note, I only missed the damned deadline by 2-3 days in the first place!).
P.S. Yes, I could have tried to extend the date of my flights.....but that, in total, would have cost me $300.00 or about 9,000 baht!