Oh, interesting, suntiger! I have been lucky in that a lot of my favorite shoes are still being made, so I just replace directly. I have bigger issues with jeans. And bottoms, in general, really.

Bottoms are problematic too, not looking forward to taking my chances online :/

I always enjoy your wardrobe wears posts. They are thought provoking, not only in terms of wardrobe planning but also on sustainability and what are really wants vs needs in our lives.
Although I have a very different ( let's call it) approach to my wardrobe I can understand how it can be almost zen like to have such a wardrobe.
To take things a further geeky step I would try to find trends and project which wardrobe item would need to be replaced and with what soon.