This is strictly my opinion so take it for what it is worth (that and a nickle will get you a nice warm cup of JACK SQUAT). I think that a collection with all the same serial numbers would have a slight advantage in value that one with mixed numbers. However, individually, I do not think it helps a knife's value. I also think it is a pride thing owners have about all their knives being "theirs" due to all having the same number. I could not afford to do this with all the knives Spyderco puts out. I do have a vanity thing that I would like to be able to do someday regarding numbered knives. I want to get a set of green handled, satin-finish Emerson Commander and Mini-C with the same numbers on both. I would really like them ot have the serial 666 (might get blasted for this one) but I would take whatever number was availible. It might happen, but probably not. Spyderco at least gives loyal customers a way to make it happen even though it is rather pricey.