Did he also tell you that using the engine will shorten the life of the piston rings.. What he says is undoubtedly true, (if you use something it will wear out) but I would want to know exactly what he is trying to tell you. Has he seen a lot of failures in the components like the throttle modulator or in the electronic control components, or if he is just telling you about something he doesn't like to fix?? I would explore what he is trying to say.