Can you wear a cotton beach sweater in the F/W? I'd like to think so. Call me crazy, but I'm doing my part to abolish sweater discrimination. Wool is warm as hell, but it's often uncomfortable against your skin and, if you're all layered up on a crisp day, can get real hot real fast. My key for F/W layering? Keeping warm of course, but staying comfortable first and foremost. I think of it like this. You wear your cotton crew neck sweatshirts this time of year, so what's the problem with wearing a traditional cotton knit? Grab one with some heft and use it as a top layer on a moderate day (over an OCBD) or as an intermediate layer if the weather is gonna dip (over an OCDB and under a parka). Right now I'm really loving this large gauge cable knit from Rogues Gallery. It's the perfect early fall sweater in my eyes - 100% cotton, but of the heavy knit variety. Sweater discrimination is in full force here (read: on sale), but you, the consumer, benefit. The thing is practically half off and a full grip of sizes are still up for grabs. At the end of the day, this ends up being a year round piece. You can't wear wool in the summertime (I mean, you could, though that would be kinda foolish), but you can definitely still wear cotton in fall, especially if you layer accordingly. A note on fit: my previous RG knits have been very satisfying - no need to size down or up in my experience.