Originally Posted by
FBinNY
This isn't to say that external BBs don't or can't last, but my long term experience is that good quality classic cup/spindle BBs outlast their modern replacements by a large margin. It used to be rare to replace BBs or bearings due to wear, which has become a more common repair with the advent of new and improved BBs.
I think the emphasis here has to be on "good quality", say Campy or higher line Shimano cup-and-cone bottom bracket spindles and cups. Cheap spindles like some of the entry level SR and Suguino bb's did pit rather quickly even if lubed and adjusted properly.