I get so tired of hearing "It's hopeless beyond 12 weeks."
The vets around here won't crop UNTIL the dog is 12 weeks old, and one waits until 14 weeks. They have an excellent success rate.
There seems to be an attitude on this board that everyone knows better than the vet because "vets don't learn this in vet school, so the breeders know more about it". My vet has been doing this for 30 years. He knows more about the dog's anatomy, blood flow, etc....he knows more about the health of a doberman than a group of breed enthusiasts on a web board. And yes, he does know more about cropping, too. MUCH MORE. Sorry, but that needed to be said.
If you are worried about whether or not you can crop your dobie at 12, 13, 14 weeks, and you feel you MUST look it up on the internet, Google "Successful cropping 12 weeks", or "why vet says it's better to wait until 12 weeks to crop", etc. You'll get a slew of results saying why it's ok.
But better yet: ASK YOUR VET. Step away from the computer and ask a real life veterinarian who crops about cropping. He/she will know more about it than anyone here, I promise.
By the way, my dog was cropped at 11 weeks and not posted until 12 weeks, after the stitches were removed. After 3 days her ears were almost standing completely on their own. They are doing fantastic.