Mazy cat went 25 days without regurgitating. Granted some of those days she ate barely an ounce of food, but she'd been back on a full diet for 8 days before the first regurgitation. She's puked every day since (3 days in a row). Sigh....
25 days is the longest she's ever gone. I would say since she was 4 years old and been on the Hills c/d for almost 3 years. That's when it first started. I don't have to rely on memory, I have it all down in the cat journals.