Regular maintenance of tankless water heaters is crucial to prevent the buildup of scale and calcium particles that can clog faucets and shower valves, causing expensive repairs behind walls. Failure to flush the unit annually can lead to sand-like particles traveling through the home's plumbing and accumulating in other systems. While tankless units are easily cleanable, lax maintenance can have costly consequences. It's important to remind customers that proper maintenance is necessary for the longevity and efficiency of their tankless water heater.