It really depends whether you're looking for a cultural experience or to make money. If you're looking to get rich - Thailand should possibly be the last country on your list, but you will have a lot of fun living here.

Those people who have worked in Thailand, Japan and Korea are almost unanimous in their verdict - You may have a nicer lifestyle in Thailand but in the money stakes, just about everywhere else is better.

There are many jobs in Thailand that still pay between 25,000 and 40,000 baht a month. Teachers were earning that sort of money back in the early 90's. I know, I was one of them. Those people who claim that teaching salaries in Thailand haven't risen in almost 20 years could well have a point.

The TEFL certificate is not currently a legal requirement in Thailand. However, many employers still want to see one. If two teachers go for a job interview; both have degrees and one has the TEFL certificate as well - guess who the job will probably go to. Having a TEFL certificate can do you no harm at all.

Having a TEFL cert will make you more employable to majority of employers. True it's not necessary but having one will open more doors for you.

Be under no illusion - Thais can be a lot of fun to teach, and other times they can be painful.
Many of them (particularly male teenagers) have zero motivation. You will have to take the rough with the smooth. The Thais expect a teacher to be a mixture of an educator and an entertainer. An old teaching colleague, who had taught in several Asian countries, once remarked "a teacher in Thailand needs to be a combination of a dancer and a game show host. If you don't have the kind of personality that lights up a room the moment you walk in, you might find yourself struggling here"

I've spent much of my teaching career here in the corporate training room. Even managers and high-flying executives can start switching off if they're not having enough 'fun'. Thailand is very much a 'let's all have fun' society.  

It's easier to say which are the worst months and the answer is December, January and the first half of April. Every other month of the year sees a relatively high demand. That certainly shouldn't put you off coming in December and January though. There are always job vacancies around but just fewer choices in those months.