Conservation as a field is holistic and encompasses restoration as well as examination, documentation, preventative care and treatment and is supported by research. With me, less is more. I stabilize the object and present it in its original state as much as possible.  The general rule of the UFDC (United Federation of Doll Collectors) is to never do something that cannot be undone. 

Although both conservation and restoration  have their own codes of ethics, it's still important for an owner of an antique doll to make an educated decision on which way to go. Generally, if an article is of great value, conservation is indicated. However, if the value is mainly sentimental, restoration can be a suitable choice. A lot depends on how important the doll is to you and what are you trying to accomplish?  Do you want to replace the original beauty of the doll to bring back all those wonderful memories or do you want to conserve the doll for future financial gain?

In general, restoration is a very complex and personal issue.  Some prefer untouched pieces, while others appreciate the merits of restoration. And there is no straightforward answer on how it affects prices at auction. That can only be judged on a piece-by-piece basis. Factors to consider are the quality of restoration, the impact of it on the piece, the number of times it's been repaired and when it was done.