With no pumps, Air coolers are a solid metal unit, and do not wear out over time. Should the fan fail after multiple years of service, it can be quickly, easily and cost effectively replaced for just a few dollars and continue to operate as if nothing ever changed. Air coolers are a great option for low to mid range builds or even high end builds in which the CPU is not going to be heavily overclocked or the ambient room temperature in which the PC will be kept does not exceed 35c on a regular basis.
While standard coolers can still provide great cooling and suit the needs to 95% of all system builds just fine, high performance premium models exist for those who want to push the limits or simply want the best of the best without compromise. These coolers differ from their regular counterparts with heavier construction, higher performance / RPM fans, thicker heatsinks and in the case of liquid coolers, higher flow pumps.