rubber bushing life question
 

So my car has more years (4) than miles on it (15k). I'm trying to understand the average life of the various rubber bushings assuming 1-3 HPDE events a year that is not a daily driver.

At what point will the steering rack, differential and various control arm bushings start to fail? Mileage is not likely going to be an issue on the car at the rate I'm going and I plan to keep the car indefinitely.

Based on your mods I'd be surprised if your bushings went any quicker than a standard street car, imo track pavement is much smoother and kinder than average street pavement, cornering loads aren't the killer, it'll be the constant deflection and movement of rolling around bumpy pavement that puts more wear into rubber joints imho.

I'm at 60k miles so far, 5x track days, bit of autox, the bushings in my car appear to be perfectly fine and I'll be disappointed if there is more than an oddball failure or two before I hit 10yr/10k miles.

I bet they use the same rubber in this car that they do in any Corolla or Impreza, designed to take a decade+ of commuting and negligence before they run out of life.

A lot of concern over the life span of bushings goes back several decades when they still actually use rubber. Up until the mid 80s or so most bushings would start to fall apart after as little as 5 years. Modern bushings have no natural compounds in them and time will have little impact. Beyond simple wear the only real enemies for modern bushings are extreme heat, extreme cold and UV exposure. If left sitting long enough the car could probably rust away and the bushing would still all be good.