Old Shoes

Is it something we women just can't gain self-control of? Is there some x chromosome gene that gives us that obsession with shoes to the point of near bankruptcy and lack of grocery money? And a current problem: Why can't I get rid of old shoes?
There's a metaphor here, but that's all I'm saying. Old shoes are so great sometimes. They're reliable, and predictable, and always there when nothing else seems to work. You know, the pair that you can always count on to be able to walk fourteen blocks in a not feel a pinch or squeeze. The pair that is just casual enough to dress down a sexy dress, but just right to jazz up a lazy outfit. The pair that you always seem to run to when nothing else is working and ten outfit changes later, you're back in the same shirt and jeans, and of course those shoes.
But they're also the pair that has that weird dent in the toe from the time you tried to climb a fence, or the scuff marks that give them character, or the weird way the heel always feels wonky on the left foot, b/c maybe they've just been strutting for a year too much.
So when do you give them up? When is it time to just drop them in the shoot and venture to find a replacement? Is it when you chance upon a brand new pair of perfect Katheryn Amberleighs that may or may not take up your next pay check (but seriously the perfect shade of aqua green dyed horse hair atop those sexy stilletos) and this is still a question?
The line of realistic utilitarian motive and pure animal (female?) desire is in question here. What are the answers? I just don't know... but I do know that I need a new pair of go-to brown flats. Any recs on where to find the perfect pair?