IMPORTANT INFORMATION: A very important aspect which decides your espresso machine longevity is water quality. If the water used is too hard it will cause the machine to have a limescale buildup, which is one of the top reasons for it's operating problems and failure. It may also destroy the machine and using too pure water, such as distilled water can cause the machine to overfill itself as the water level detector needs minerals in the water to detect water. The best water which should be used is softened water, about 50ppm in hardness or less. Must follow manufacturers instructions while descaling the machine.
In general, if the water used in the espresso machine is kept at a hardness level of 50ppm or less, descaling won't be often needed. A warranty usually does not cover espresso machine or it's parts failures, such as heating elements, water level probes, sensors, pumps, etc, caused by hard water usage and not descaling on regular intervals when hard water is used.