I try to do the best I can picking the layers etc. for day's conditions. Most of my rides start with a ~4-mile descent. So, in cooler weather I often start with a very lightweight wind jacket. Once I'm down the descent and warmed up, it easily fits in a jersey pocket. I have a Castelli Ros vest that has been a wonderful piece of kit. Wind blocking up front, very breathable in the back. Packs up small enough I can fit it in a jersey pocket if needed. Rarely I'll make use of arm warmers. That's only if I know it's going to warm up a lot. Else, I'll wear a long sleeve jersey.

The jersey pockets can get pretty full if I have the wind jacket, vest, arm warmers, ride wallet and a few gels in them. But it's sort of amazing how much crap you can stuff in them and you don't even notice it while riding. At some point in the winter, I'll mount a frame bag so, I can deal with more layers. Always a hassle to dress right in the cold temps.

I guess I'm a bit of a wimp. If the bulk of my ride is below 60 F, I'm wearing tights, long sleeve jersey, vest and likely full gloves. Below 50 F, it's double layer of tights, wool base layers and soft shell jacket, skull cap, and thick gloves. Oh, and winter riding boots. But heck, it can be in the 40's and I see guys wearing bib shorts, and short sleeve jerseys. I'd be freezing dressed like that. I may not be laying down pro wattage, but I'm not cruising either.