It really depends on one's particular circumstances. I live here (Phitsanulok) full time. On one hand costs are cheap - go to the market, food stalls, bread 36 baht a loaf, water 7 to 10 baht a bottle, etc, etc. On the other hand the funds that finance this lifestyle come from Australia, my army super, and so the exchange rate has affected the extras I can buy. When I came her 10 plus years ago I got around 25 baht to the dollar; now it's just over 20, so my slush fund has taken a hit.
Having said that, I have no intention of going back. Home is here now, but I do hope for a rise in the Aussie dollar, sooner rather than later.