I would add that on Guenevere, we only use teak oil in the cabin. Every few years we clean the teak with Amazon's teak cleaner. It's a gentle one part cleaner. You can see it at; http://www.amazon.com/Amazon-Step-Teak-Cleaner-Quarts/dp/B0014438H8
we then use Amazon's teak oil. A few Light coats a day or so apart.
Just a note here, this stuff was named Amazon long before the ".com" was here.
That's for the main cabin. In the head, we cleaned ALL the teak (a lot in our boat) very good. Then let it dry out for a few days with no use. The we used a couple of coats of Deks Olje part one (mat finish). See it at; http://www.jamestowndistributors.com/userportal/show_product.do?pid=168&engine=adwords!6456&keyword=deks_olje
We shower in there a lot and it has kept the teak looking new!
Just what we did.
Greg