coil spring lifespan
 

Is there an average lifespan (milage) on the stock springs? Mine got 113k on them, but my mechanic said they are probally still fine.

The life a spring depends on a ton of factors - some of which are its quality, road conditions where you drive, how you drive, the weight of the car, and how well damped it is. I'd say after 100K they are probably a little tired. I have only heard of 1 Mustang that actually broke a spring - the stock one gave out at about 160K on a friend's 5.0.