I put a set of ECS on my car in May 2018, drive an average of 700 miles per month, and run winter tires for a minimum of 3-4 months per year, depending on the weather. Tires are rotated whenever I swap from summer to winter and back, since I don't go the full 7500 in one season.
When I removed them to install my summer tires in November 2019, one pair were down to 5mm, the other pair were at 3mm left and 8mm right, since one of them was replaced after a puncture in December 2018. I checked my maintenance log, did some math, and found that I've only driven about 8500 miles on the set. All miles are city/highway, no track days, though I do treat on-ramps as playgrounds, when I have them all to myself. Despite wearing much faster than the 30,000 mile guarantee would have you expect, they're still smooth and quiet enough that the accelerated wear came as a bit of a surprise. (I did install a JB4 last summer, but I haven't gone past map 2/3.)
I'm going to see if Discount Tire can get me a pro-rated price on replacements once the weather warms up, but even if they can't, I'm not really mad about it, since I've been more than happy with them throughout my ownership, and let's be honest: buying performance tires based on how long they're going to last you is like picking a new television based on which one has the best sound. You're doing it wrong.