My record for wearing the same wool socks is 7 days. They didn't smell so much as become uncomfortable from salt and gunk. I normally wear them two to three days, alternating pairs every day.
When it gets sub freezing I wear water proof hiking boots. The synthetic socks I wore to start with made the mother of all funk by the end of the day inside those. Not that the wool socks are odorless, but it's a huge difference.