This is an interesting question, I feel like a lot of us, especially myself just make impulse purchases when it comes to contemporary bags since they're always "on trend" and affordable vs the timeless silhouettes of some premier designers. I agree with a lot of the other posts that MK doesn't really offer anything that's timeless seeing as it's a contemporary brand that offers bags that are "current". It does have bags that it is well know for such as the Selma or Sutton, however many other brands offer similar styles as well.
I started to focus on bags that were more functional for me primarily totes or crossbodys, because I like being hands-free and also because I know I'll make use of them over time. I also made sure to choose neutral colours (black, browns, taupe, navy, greys, etc.) but started to buy wallets and accessories in colours that contrasted or were seasonal so I didn't feel like I was missing out. Once the item loses its novelty, I'd still have a bag in a colour that still looks classic instead of outdated, and still have the option to buy new accessories.