I know this question wasn’t directed to me, but one of the big changes for me was moving from the suburbs to a city a decade or so ago. I use public transportation more now, so things I used to leave in the car, like an umbrella or water bottle, now go in my bag. Also, my town and the town next door have implemented a plastic bag ban, meaning that if you buy anything at all and need a bag, you pay an extra 10 cents. It’s not a huge amount, but I try to always carry a reusable shopping bag with me. It’s a small thing but can take up a lot of room!
Another thing: when I’m out with DH, I am almost always asked to carry a pair of his reading glasses. When he asks me why I don’t wear the Chanels he loves so much, I tell him that part of the reason is they won’t fit his stuff!