lower end of acceptable in my book
What the heck wore out? In my book, running shoes need to be broken in. And 250 miles is just about a decent break-in period. Now they should be molded to your feet and beginning to feel comfortable. Why throw them out?
I don't throw them out but when the outside part of heel is so uneven, I think it puts more strain on the ankle. I knew you two guys especially Chi town keep shoes running forever even when there is even a hole in the bottom. But my running style seems to wear out the outside part of the heel sooner than other parts. So the shoes become light duty, which I have a lot of them. This also makes a $100 shoe cost about .40 cents a mile. At least with O shoes you can justify that because of such abuse from orienteering.
Your running stride must be a bit pigeon-toed, to wear the outer part of the heel. Can't believe that doesn't have repercussions with your knees. Maybe you need an orthotic?
go to a shoe store, show them your old shoes and ask them if they recommend a shoe for your situation...and, go to a trusted PT, show them your shoes and ask for advice. Even if you decide to do nothing, you will have a better understanding of what is happening and what your options are.