Your Subaru fuel injectors are key members of the team of parts that make up your fuel system. Their proper functioning is essential to the performance of your Subaru. That means that you'll have to be attentive to their needs and their maintenance schedule if you want your Subaru to continue to be the reliable and fine running vehicle you've become accustomed to. The general estimation of professional service for your Subaru fuel injectors is about 40,000 miles. That, however, should serve only as a guideline, as the life span of your Subaru fuel injectors involves a variety of factors. Quality of fuel, individual driving style, and day-to-day driving conditions are just a few of those factors. Poor fuel quality can lead to your Subaru fuel injectors becoming clogged and experiencing hesitation or sticking in opening or closing in response to the engine's changing demands for fuel, as can repeatedly running out of fuel. Highway driving and city driving are different, and can also influence the wear and tear experienced by the inner mechanisms of your Subaru fuel injectors, as can individual driving styles. Therefore, instead of relying on a specific number of miles to tell you that it is time to service or replace your Subaru fuel injectors, you should keep an eye out for symptoms of fuel injector difficulties. These include difficulty in starting when the engine is warm, a rough idle, decreased gas mileage, a smell of fuel in the passenger compartment, and rough running that increases as the engine warms. If, when checking the source of these symptoms, it turns out that your Subaru fuel injectors do need to be replaced, do not put it off, as you can cause damage to other parts of the fuel system.