@Pertti ************
having a work permit under a type O extension based on Thai wife makes no difference in citizenship, or permanent residency. If you are not married to a Thai then the road to citizenship becomes a much lengthier process, as you have three years working before you can apply for permanent residency, then you have 5 years after that before you can apply for citizenship, continuously working the whole time, and making at least bt80,000 a month if not married. If you are married, you can do it in three years, continuously working making at least bt40,000 a month. This is easier to do on a type O extension. Being under a type B visa extension puts your whole time at the mercy of who you work for, as they can cancel you, and use that as leverage over you. They can't do that with the type O extension. Just something to understand