Should I get a 30-day extension in Thailand or apply for a Tourist Visa beforehand?

You know how you sat at your computer and made this post asking this question? That's the same way you would apply for a tourist visa.

Meanwhile, if you came in on visa exempt and had to get an extension in Thailand, it means you will have to worry if your airline is going to require proof of onward travel within 30 days before letting you check-in, you're going to have to plan a day of your vacation to go to the immigration office. You'll need to ask wherever you are staying for a copy of your TM30. You will need to travel to the immigration office and back (in Bangkok this can be 1+ hour each way). You will need to wait in line for the extension (once again in Bangkok this can be 4-8 hours). Other immigration offices in smaller areas are not likely to take as much time, but still much more time and effort than applying for a tourist visa from the comfort of your own home. Oh, and for most Thai embassies, the tourist visa is actually cheaper than an extension, and that's before you factor in transportation.