How long can I stay out of Thailand on an O-A visa without it expiring?

The O-A visa allows for a one-year stay in Thailand from the date of entry, and it's multiple entry, meaning you can leave and return multiple times. To maintain its validity, ensure that your total stays within Thailand do not exceed the parameters set by the visa's entry conditions, which are guided by the 'Valid Until' date on the visa itself. Thus, you must be cautious about how long you remain outside Thailand to ensure your visa remains active.