We don't do technique/fundamentals and rolling in the same class, we do one or the other. Sparring classes are an hour long. Anywhere from 5-10 minute rounds, but 7 is the most common. Maybe 30-60 second break between rounds - however long it takes to grab a sip of water and a new partner. So I guess 5-9 rounds after warm up, but its an hour regardless.
People from other schools usually compliment us for being "in shape" when they drop in for a visit. Probably because they're used to 20-30 minutes of sparring after a fundamentals class instead of going an hour straight. The bigger guys or the more casual/recreational practitioners think it's funny because they don't consider themselves to be athletic at all, they're just used to it.
A few of us usually stick around after to drill a few things and do a proper cool down/stretch.