So if you're washing the dishes or going to do some physical activity which requires you to sweat profusely, take your watch off. It'll extend the strap life to 1 yr+. If you do get the strap soaked, take your watch off and let your strap dry.
How long a strap lasts for is very subjective. When is the strap considered "in need of being replaced?" When the strap doesn't look new anymore? When the strap and stitching is falling apart? When it starts to smell?
I might be able to overlook some fraying in the strap stitching, but someone else might be turned off by the fraying and consider the strap "in need of being replaced".
Everyone has his own criteria, so a leather strap that won't last 6 months is a very subjective statement.
- Anthony