One Thousand Years
I've always wondered why people say that ninetails are known to be unlucky. We can live for one thousand years and our tails have supernatural powers but that can't necessarily be a badthing can it. Our tails can do things such as preserving a person or pokemon's life. An extremely good example of this was to protect blane from dying by cancer. I am the reason that he has no hair. For a ninetails to heal or preserve a human life the human must sacrifice something. It doesn't have to be that big of a deal, something such as hair or their favorite outfit.
Another thing our tails can do is that if a human wants to be a pokemon, to study a certain pokemon we can do that. That is where pokemorphs come from. Granted the human can choose the pokemon soo yeah. They in their pokemon form is the shiny form of that pokemon and theirfore never seen. If one is cauptured they usually disobey their trainer so they are often let go.
We are always looking to help others so we are normally kept as family guards to watch a father's children's children's children. We are forgotten over time but we don't care. We watch and learn.
One thousand years can be a long time to live but we don't care, much. We have to watch our friends die and our powers are muted after our trainer dies. We still watch. Watch and learn. One thousand years is a mighty long time to live.