I don't know about you but I prefer different bags for summer v winter. And I don't mean - don't wear a straw bag with a winter coat (I actually don't even have a straw bag).
I like to wear fabric shoppers in the warm months, casual and practical choice. My Bao Bao tote is a summer bag. I often don't like to wear a crossbody bag with my summer clothing and my hand held bags come into play.
For winter I need crossbodies and I rarely carry a fabric tote. I need to be able to hide my hands in the pockets. Also a bag should be big enough to hold gloves/mittens and the rest of my things, not too much of it but I carry keys, my phone and a small wallet.
Only a few of my bags crossover the seasons. Because there is one more requirement that is important to me - proportions. I wear a couple of my crossbody bags all seasons but I don't like proportions with puffers. I have one bag that I wear with outwear, it has a wider strap and works better over a chunkier layer. I would like to find something else, though, something more interesting. I was sure I would buy a Bao Bao backpack but hesitated. I might still go for it, need to make a decision soon.

#1 winter bag, #2&3 all season, #4-6 some of my summer bags.

So, how about you? Do you have seasonal bags? If yes, what are your requirements? I understand that in the colder weather especially, lifestyle dictates most of the fashion choices. I don't drive and my style is urban, so these two things define my choices first and foremost.