I consistently get 7 days out of my Gillette 7 O'Clock greens (SS). I follow the Gillette recommendations of old: rinse, dry the whole assembled razor. No need to disassemble or dry blade. I've never seen any rust on blade after a week. Not sure how 'water dulls blade' if it's not on the edge. Patting assembled razor dry takes care of water on exposed edge so the few drops remaining inside on the flat of the blade are irrelevant.