Number of days is such a useless metric, though it seems to be the favorite. Everybody is different and some people will make good socks in one day, some will take 3, 4, 5, or longer. It’s all about the individual, how they’re wearing them, and what they’re doing in them. Think about wearing socks for 4 days sitting around with shoes off, compared to wearing them for 4 days of 8-hour work shifts + workouts - those are going to be completely different socks! Of course, besides activity, other highly influential variables include what shoes are worn, how much they’re kept on, how socks are stored between wearing (they shouldn’t be allowed to air out), and also the type of socks - nylons are actually more difficult to get stinky than thicker socks.