wrote in message
Just bought the wife a nice set of Kitchen knives for Christmas, and
had heard the advise to hand wash them only, I suppose because the
granular
dishwasher detergent might dull them.

I believe it's because dishwasher detergent is more caustic than the type
you'd use for handwashing. In the long run, there really isn't enough
difference to cause you to worry. It's likely you'll be old and grey (or
greyer) before you'd consider them damaged.