I bought my 2007 cx-7 in june 2006 and it came with the lousy turanzas that were pretty shot by 20-25k, but I stuck with them until like 35K.
I replaced them with pirelli scorpion zero tires and I'm at about 79,500 miles on my car and the tires are still running strong. 2 of them are showing more wear that the other 2, but still have some life in them. So, that is about of 45K on my tires. I will say they have done an admirable job, I'm in Boston & they did great in the snow for the last 2 winters. My only problem is road noise, once they got like 25K on them it started getting a bit loud but hasn't gone up too much since.
I could get more life out of them but worried about snow grip this winter, so I just bought 4 Yokohama Parada Spec-X on tire rack. I'm having them delivered to the mazda dealer and they will install.
The only reason I did not go with the pirelli's again which treated me great was the price. The pirelli's are $182 and the yokohamas are $139. I hope I did the right thing.
Anyway, my 2 cents.