...And I rarely eat out, drink only at home where it's very cheap, have a wife so don't spend any money on "other" ladies (except support for my mother-in-law), no mortgage, no other debts (paying the final car payment this month), and we average about twice that much per month... guess it just depends on what your standard of living is.
If you're single, and as cookman said, don't drink too much or dabble in Bintabat too much I guess you'll be alright.
Home maintenance, clothing, laundry, electric, water, telephone, internet, transport, insurance, pest control, medical including any medicines you normally take, housekeeper or gardener if you need them, TV (TrueVisions/Cable), visa expense, etc., are all things you will have to decide if your budget can handle and still leave enough for food, fun, and any recreation, sports, or travel you are hoping to enjoy.
We own a home so have no rent and all the other things I've mentioned (before and not including the food, fun, recreation, sports, or travel) costs us more than what your monthly budget is. There are a lot of people (including me) who thought they could live like kings on that much only to find that they are confined to the house, Chang beer, TV and the internet for entertainment to get through the month.
Make sure you plan well for what your needs will be and know the costs of items you require in your life.
Also, I don't know how you are planning to stay here, but you can't get a retirement visa with an income that low unless you have 800,000 baht to leave on deposit.