Unless there is a medical necessity (eg. someone slammed the dog's tail in the car door and it's hanging by the skin) you should not amputate a dog's tail.
When docking is done at just a couple of days old, the nerves are not fully developed. Aside from that meaning that the dog suffers little pain (not even anasthetic is given), it also means that they are unlikely to suffer any ongoing nerve problems that are so commonly associated with amputations. Ask any person with a limb amputated about "phantom pains", or do an internet search - you should soon see why amputations aren't something you do for cosmetic purposes or to protect what's on your coffee table. It should be done ONLY if it is a medical necessity.
Bear in mind also that this is a major surgery, and involves all the risks of anasthaesia. Unneccessarily and without benefit to the dog.
It is certainly not common practice to perform amputations on dogs of any age for cosmetic reasons and I'd be surprised if you found a vet willing to perform that sort of uneccessary surgery anyway.
