@evan Depends. If I'm quick, it takes me about 10 minutes (with washing hair and all, I can try to do it quicker but will either fail or still have icky hair). If I'm trying to fix my body temperature or ease pain or tension, it's easily half an hour. Most of the time I try to be quick but get distracted and take around 15.
I no longer shower daily though. Usually 3 times a week, washcloth washing at the sink on other days. So I reckon that 2x 15 and 1x 20 on average is still better than 7x10.