I custom build my own wheels. The first one I built was a spoke replacement for a replacement wheel whose spokes collapsed after 6 months. My build is still going strong 4 years later.

Of course, that doesn't mean all custom/self-built wheels are all that strong. Depends on the parts too. Last year I built a wheelset with very lightweight spokes (DT Revolutions..) I ended up replacing the drive side of the rear wheel with heavier spokes (Dt champions.)

And, to be perfectly honest, I'm still riding on the original, factory-built wheels on my Bianchi Volpe after some 12000 + miles.