Many factors affect the life of a starter motor, but certainly HEAT is one - excessive heat can shorten the life of the starter. There are only a few threads, of higher mileage RDX starter failures.

On inline engines the exhaust often runs past the starter motor, but not so on the RDX. Would a heat shield or heat "blanket" provide protection to an RDX starter? or would that only cause more heat-soak?

After all, the radiator fan is blowing directly onto the starter. Engine coolant radiator "exhaust" heat is not nearly as high as exhaust pipe heat radiation onto a starter.

Any comments, thoughts, or ideas for increasing the life of an RDX starter?

 

you could wrap the starter and also the exhaust?