I'm wearing a shell vest today over a white button-front shirt, and it has occurred to me that although I wash my shirts after every wear, I don't think I have ever washed the shell. I've owned it for about a year and I've probably worn it seven or eight times. It never touches my skin, never gets body oil or sweat on it, it hasn't been spilled on and smells perfectly fresh. However, it seems weird that it's a regular item of clothing -- i.e. not a coat or jacket -- and I haven't washed it.

I wear merino sweaters over white shirts sometimes too, and I wear them many times before I get them dry-cleaned. They don't touch my skin either. I guess I treat them the same way I treat outerwear.