Why do you need an agent? It's usually done by the consulate in your home country, which agents can't help with. You can't apply for the DTV from within Thailand. Agents can't go to immigration to process these, unlike some other visas. You have to prove you are physically present in another country for that consulate to help you.
It's one of the most common procedures done by thousands of tourists every day. Don't let it stress you out. It is extremely simple and routine. But read the guidelines already posted so you bring the proper documents with you.
since this visa must be issued in other countries, and rules vary so greatly from one consulate to another for how the funds must be proved, it doesn't seem like something most agencies can help many people with.
There are hundreds of posts of people doing it on their own. Few seem to have needed an agent. Why use one for such a simple process? It's one of the easiest long stay visas to get.
if I understand the OP's post though, they are saying they wish to continue using the old passport (presumably for entry stamps) since it still has space, even though the DTV was issued for the new passport. This is what doesn't make sense, as the old passport should have become invalid as a travel document when the new one is issued, so can no longer be used as the entry passport. This is not the same as having a valid visa on the old passport, which can still be presented to enter on the new passport.
did you read his other post where he insulted old people and was upset at people for calling him out? That's why people are reacting as they are to this new post from him.
did you read his other post where he insulted old people and was upset at people for calling him out? That's why people are reacting as they are to this new post from him.
Most passports become invalid once you get a new one. Many countries even require return of the old passport first so that it can be corner cut or otherwise indicated as no longer valid, before they will give the new one, regardless of whether the reason for getting it is because the old one expired, or is damaged, or is running out of pages. Is that not the case for your country?
because there are people who either don't qualify for visa exempt entry due to their nationality, or people who have entered many times nearly back to back by visa exempt entries before, and immigration may be less likely to deny them if they have an actual tourist visa. It was your responsibility to decide if you need a tourist visa. The consulate has no problem selling the visa to you if you apply for it. They don't know the circumstances of why you feel you want the visa.