In practice, a PHEV like the Volt is more reliable and has less maintenance than an ICE vehicle. The engine in the Volt only runs in the rare cases where the ba

In practice, a PHEV like the Volt is more reliable and has less maintenance than an ICE vehicle. The engine in the Volt only runs in the rare cases where the battery charge is low. When it does run, it generally runs at a constant, low stress RPM while supplying power to the electric motor with buffering from the battery. This is generally acting like a series hybrid. (The parallel hybrid mode is only activated in some rare cases). The result is that the EV motor is used for most miles and the gas engine lives a rather pampered life. The car also keeps track of gas miles and gives you an estimate for remaining oil life. Under typical usage, that results in an oil change every couple of years. I think that the spark plugs are 100K plugs so they will eventually need replacing but not often.