It depends to a great extent on the woman's technique. If she's really good she can keep the experience going for quite a while. Using mouth only, it tends to take me awhile. The more she uses her hand to pump my shaft while she suck the head the more quickly I'll cum. But it does usually take a while, it's not just a minute or two, or even five.
@ChipmunkErnie My first wife would get a tired jaw when working on me, so she solved the problem by using butter -- squished/melted in her hands, she'd suck me for a while, then use the butter as lube and pump me by hand to get me closer to cumming, then go back to using her mouth to finish me off. And the butter/cum mix tasted better than using oil.