The process of cloning might not be that new per say, but to the majority of people, it's just a theory or an idea yet to be actualized. During the course of my research, I was able to come across certain projects where body parts were cloned for animals and they seem to work pretty fine. Am yet to come across any case where human body parts have been cloned, or maybe it has, not officially though.
Drawing from the above and my understanding on how cloning works, extending the lifespan of a human via cloned organs won't be possible. Remember it just an added single organ and not a full body clone. To extend a human lifespan through cloning, a 100% process including Molecular and Cell cloning has to be done. In doing so, every single part of the body, in and out, becomes new and can begin to function energetically untill time takes it course and weekens the body again like the natural cycle of life, begining with a body growing older by age.
For the record, I think organ cloning is a very much welcome idea, health wise. It is a process that will help save a lot of lives, am talking about certain people faced with death due to one or more organ failures. A cloned organ will give such people another chance at life.