The current recommendation for most healthy patients is to wait about 7-10 after a sinus illness begins to start antibiotics. It has been shown that most of the time this is a viral illness and antibiotics too soon will just cause antibiotic side effects like stomach upset. Many patients with recurring or chronic infections may benefit from treating infections sooner. If you are someone having recurring or chronic infections, it is recommended to have a sinus evaluation and likely some imaging such as CT scanning or nasal endoscopy to get a handle on what's going on.