I run 500-700km in my shoes before they become my walking shoes. The shoes just can't take it much more and I start to lose traction or feel some discomfort in the feet.
Running shoes are definitely expensive, but if you're running a lot then the possibility of injury exists so I like to be on the safe wide with my "equipment" which is mostly the shoes.
Dang, that's unfortunate. I'd rather not buy any additional hardware. I can cast from windows to the TV easily so I know casting is possible.