I got my C-Max Energy in Feb 2017. I don't drive much, only 13,500 miles, 70% on Washington DC streets.
Just got my tires rotated. Dealership measured after the rotation. 7/32 on the fronts, and 3/32 on the backs. They told me I should probably replace in the spring.
I don't drive aggressively, but that's a lot of wear on only 13,500 miles.
Costco has a deal for 70 off tires, 40 off installation on the Michelin Energy Saver A/S.