Difficult to know what you are asking.

You have a Single-Entry tourist visa right now, but haven't used it? If you're received an SETV eVisa, it's valid for 90 days, and you can enter the country any time within those 90 days.

If you'll be getting an SETV before coming here, yes, you'll be able to extend the 60-day SETV for another 30 days at immigration for 1,900฿.

Same thing for the visa-exemption stamp, but if you enter in October, it'll be 45 days instead, and you can extend for another 30 days for 1,900฿.

@Jackie ********

It's a requirement everywhere. Not with police directly (that would be a bit extreme), but in the TM30 system. Simply ask your landlord to provide a TM30 for you. You print it out and then go to the back at immigration to do a "TM30 receipt" (which they/you staple in your passport and take photocopies of when need to).

You need to ask for a new TM30 and do a new "TM30 receipt" every time you stay at a hotel, since the hotel staff will do a TM30 during your stay at the hotel.

@Glyn *********

Stamps in passport are still a serious issue. Especially when applying for a visa in another country, or when an IO looks at your passport.

@Gibbs *****

lol, buzz off.

@Tod ********

OP asked "I know that when I return to Thailand I have to show immigration both new passport and old but my question is where should I let them stamp the entry stamp?"

Like the staff at my consulate told me, you can't get a new passport without cancelling the old one. Once your new passport is cancelled, they give you your new passport. The transfer and the validity of the stamps is separate from the validity of passport, though.

Once you get a new passport, your old passport is invalid. Although you can transfer things to your new passport.

@Carma *******

The photocopies you handed to the school were your visa, and maybe TM6, and TM30. If you leave, all that changes.

You're a genuine tourist, and look like one in your passport and visits to Thailand (left in between short visits). No need to worry at all. Have 10K baht equivalent in cash, proof of onward travel and a hotel booking if you want to keep it on the safe side.

@Lisa *******************

Still, not official yet. Should mention that it's in the works, and will possibly happen. If it doesn't go through and he uses your advice to book a flight 15 days too late, he will lose a bunch of money.

@Lanny **************

METV is best for long-term plans ("as long as we can"), which you can only get in your home country. Even if you think you might not need all the re-entries of the METV, getting a SETV from an embassy in a neighbouring country, like you are thinking about, is a hassle, and will probably end up costing you more in the long run in travel costs. And getting multiple SETV's is more and more difficult, the more SETV's you have in your passport.