Unlike Nige, I consider myself a "Grand Master of the Doesn't-Work-at-All-Print".
I have a trashcan full of them, which I empty before every darkroom session.
My postcards (I've withdrawn from that for a while) were made from negatives which required an absolute minimum of manipulation; the prints for the other exchanges are drawn from the negatives I feel I might make work in some way. One of them had a base exposure of 5 seconds, with most of it burned in at up to 120 seconds...
I make one print first, then have it framed. I then give it to my wife to hang in her office - if she wants it it's at least "promising". If it stays up for more than a week it's good. Twice I've received requests for prints for her colleagues - I take that as an indication that they're good.
What I like about the print exchanges is that they give me both an indication of what others consider to be their best prints; as well as giving me an opportunity to show off some of my best efforts. I admit to having used "substandard" packaging on occasion, and intend to improve on that.
So now I really should start thawing out my darkroom - it was -2C there today