We have an all-wheel drive Subaru. A few months ago we had one tire blow on a set that was around a year old. We were told (by the tire store) we had to replace all of them. That sounded nuts but I researched it a little and it appears to be true. $870 for 4 high-performance tires.
Now, around 4 months later, we have blown another tire. The (same) tire store is telling us it's okay to replace just one tire because of the age of the tires. They are under warranty.
This sounds reasonable, but I just want to make sure this isn't a case of the tire company getting out of replacing all of the tires. Are there any guidelines for tread wear where it's not safe to replace a single tire on an all-wheel drive vehicle? In this case we were told there was 11/32 tread depth which I guess is like new.