Sounds like you haven't been rotating your tires.....like me
. In my case I had no idea they were wearing so fast and by the time I had noticed the fronts were quite worn. I did rotate them to the rear(the rears were pretty good) and managed to get another 6 months at the rear but once the rears started looking like slicks and winter was coming, I replaced all 4.
Thing is the way the price tires, the specials are only on a purchase of 4 tires. Costco frequently does a purchase-3-get-$70-off, special which I took advantage of. Note not all Ecopia's are crap like the OEM Leaf tires, the Ecopia +'s are much better than the OEM Ecopia's. I'm also running the max 44psi on my replacements and they've been wearing MUCH better than the OEMs.
Leaf tires aren't cheap, expect to pay close to $500 even on sale, damn wide tires