What should I do if I only have a year left on my passport for travel to Thailand?

You can NOT apply for the DTV.

Yep, I do read the comments of people who make their own regulations.

If you're smart at all, you'll start renewing it within the next 60 days, that simple. The probelm? You will have to go several weeks without a passport, be absolutely certain anything important you have to do that WOULD require it is handled. For example, you better have a hotel room booked for at least 90 days straight cause you wont' be able to check-in to a new one w/o a passport. I went through this last year myself. Asked an Airbnb host to check my passport a couple weeks BEFORE move in since I wouldn't have it on move-in day. Luckily it was a landlord i already had a relationship with.

Get a new one then apply

get a new one? 😅

If you haven't applied yet, get a new passport before you do so. Even though you have a year left, most countries (including Thailand) require at least 6 months of validity to enter. So you will need to get a new passport in the next couple of months anyway. Then, after you get a new passport, you have to go through the hassle of getting the DTV transferred to the new passport and carrying both with you, just in case. So do yourself a huge favor and just get a new passport before you apply.

In regards to what?

One year left means that you have one year left and will need to renew it if you want to travel.

Most places require atleast 6 months left on the passport

You might easily apply for the visa and travel until the passport have six months left and you should also be able to do land border bounces beyond that time, but you’ll need to carry both passport all time together with the DTV.

Get a new one 🤷🏾‍♀️

You will need a new one.

It will be invalid after a year. But some countries accepts expired travel documents within 1 year of expiration. For example EU citizens can travel within the EU and Serbia and Switzerland, etc. too with expired documents within 1 year after expiration.