How early should I approach the Immigration office in Phuket for a Tourist Visa extension?

The user is inquiring about when to approach the immigration office in Phuket regarding a possible 30-day extension for their Tourist Visa, which expires on 10th September. According to comments, it is recommended to go to the immigration office up to 45 days before the expiry date, and doing so early will not disadvantage you as it will simply add on to your existing stamp. The user can visit either the Phuket town office or the Patong office for this process.