Urrm. It takes me around 15-18 minutes when I'm not shaving. When I'm shaving round that up to probably 25 mins.
That said, I have a LOT of (head) hair! lol So I have to use a lot of shampoo, means more work to rinse it out, then the conditioner and getting the tangles out, and rinsing the conditioner.. yeah, takes time!