How soon can I apply for a 30-day extension to my visa exempt entry in Thailand?

The best time to apply for a 30-day extension to your 45-day 'visa exempt' entry is when you have 30 days or less remaining on your current stamp. Most immigration offices allow you to apply at this point, adding the extension to your existing expiration date. It's advisable to prepare all necessary forms and visit early in the day, as you may need to return in the afternoon to collect your passport. Some offices, like the one in Jomtien, may have different rules, so it's important to check with your specific location.