I have never gotten 400 miles out of a shoe. I'm 190lb runner and have gotten as low as around 200 miles and looking back through my Garmin retired shoes managed 370 once. At any rate, shout out to these Brooks Ghost 13's :)
Normally something (knees) let me know it's time to switch. These I retired due to running out of sole! At any rate, 95 activities, and 444 miles is a record for me!
For me I start to feel a bit more impact forces on my knees once the midsole is starting to go flat.