While there is much discussion about which bearing protector works the best, it is safe to say that the worst bearing protector will protect bearings significantly longer than the best oil seal.

That's why the use of oil seals in ANSI pumps is rapidly diminishing in favor of bearing protectors. Bearings can have a legitimate design life of several decades. But if you take the time to study the information provided by the oil seal industry, you’ll find that the legitimate design life for oil seals in typical applications is measured in days up to a few months.