Sometimes it seems that 99.99 percent of the engineers who specify a fan for an application do so with the assumption that the fan they specify will run forever and never experience a performance problem. For a gambler, those are pretty good odds, and for the majority of fan applications the assumption is a safe one.
But what about your customer's fan application? Is their fan just another piece of hardware, or is it an important part of the process system? Can they afford to ignore it, entrusting its future care and operation to the operators, the maintenance department, or to people who make production decisions without ever going near the equipment itself? Almost always, they can. Almost.