Can I extend my Thailand visa before it expires or do I have to wait until the last day?

The user inquires about extending their Thailand Tourist Visa (TV) for an additional 30 days at the immigration office in Samui, mentioning that their current visa expires on February 16th. The main concern is whether they can apply for the extension a few days before the expiration or if they must wait until the last day. Comments indicate that extensions can typically be requested 30 days or less before the visa expiration date, and that Samui immigration may prefer applications to be made closer to the actual expiration date.