Is it too early to apply for a 30-day extension on my 6-month tourist visa?

A user inquired whether it's too early to apply for a 30-day extension for their 6-month tourist visa after having been in Thailand for about 3 weeks. Responses indicate that most immigration offices generally allow applications for extensions when there are 30 days remaining on the visa, while some larger offices may accept applications with up to 45 days left. However, in places like Pattaya and Koh Samui, applications might only be accepted in the last week of the visa's validity.