There is no reason to go back to the old attorney. Your new documents simply supersede the old ones. In your case, you have the original documents. In some instances, the attorney holds them. If that were the case, it would be helpful to the original attorney to let him know after you execute your new estate plan so that he doesn’t have to keep the old estate planning documents secure.
Most law offices have several fireproof safes stuffed with estate planning instruments, some of them for people the office hasn’t interacted with in decades. The law office could use the additional space.
For the five components of a good estate plan, check out this article.