When I changed handbags daily, I used the same wallet and cosmetic case for 4 - 6 months before switching (usually for more seasonal colors). Now that I change handbags less often I'm inspired to coordinate my handbag accessories with the handbag color or trim. So, I end up changing the wallet/etc. once or twice a month.
I may not be using as many handbags, but I'm using more of my accessories. And of course, finding the 'need' to buy more accessories in coordinating colors.And I've noticed that now that I'm paying more attention to the accessories, I want the color of those accessories to work well with each other, with the handbag color, and with the handbag lining color. The red linings on a majority of Dooney handbags make this a challenge for me. Between the color of the lining, the color of the handbag, the color of the handbag trim, and then the color of the accessories.... it can be too many colors at one time. And matching the accessories to the lining makes them hard to find inside the handbag.
I think it's why I try to keep some things simple. My projects are very detail-oriented, so I try to conserve brain power for that.

One other thing: I do have special bags for when we have inclement weather. And then it's all about matching the bag and coat! I can't stand a black bag on a navy coat. Can't do it. But it will work the other way with my dark navy bags. I don't know why that is. And green with black, never.