That's because there are too many people on here causing confusion because they talk out of beliefs, backsides and not experience. You will be given a list at immigration and a form to do, also to provide documents. Even so, you might be better asking an agent. Your choice, take care.
Yes, lve have METV. Flew to Hanoi, stayed 5 days, no problems on coming back to Thailand yesterday. IO only asked how long was l staying this time. A visa agent will look at your circumstances and say ok. Basically your good to go. I paid for fast track at Bangkok because the immigration ques were horrendous.