How do doctors decide when to give antibiotics for a sinus infection?

[Richard.C]

I've had a nasty sinus infection for a week, and my primary care doctor decided not to prescribe antibiotics, explaining it was likely viral. I understand the concept of antibiotic stewardship primary care, but it's frustrating when you feel awful. How do doctors in a busy clinic actually make that call? Is there a specific set of symptoms or tests they wait for, or is it more of a judgment based on experience?