Basically, we have several camps going. Not all are created equal.
1. "Dog years"--werewolves don't live long. Almost no one uses this.
2. "Human years"--lycanthropy does nothing to life expectancy. Either the metabolic changes cancel each other out, or it doesn't involve metabolic changes. (Magic spells and the like, or interdimensional astral phenomena, etc.) Again, not really used.
3. "Preferred Insurance Client years"--werewolves live as long as a human ideally should. If someone does all the right stuff--eats healthy, doesn't smoke, keeps alcohol in moderation, etc.--and manages to avoid random things like cancer or getting hit by a bus--then a person theoretically can live to a hundred or more. This is where the overwhelming majority of us appear to be. But, then again, I haven't read a poll on it.
4. "Elven years"--werewolves can live for hundreds of years or more. A bit reaching, but this goes with the idea that the regenerative capability of werewolves applies not only to shapeshifting but to other metabolic processes, such as aging, cancer, diabetes, and the like. It's not that much of a stretch beyond shifting itself, but creates plot problems unless you actually want ultra-powerful characters.
5. "There can be only one."--werewolves are immortal, unless you cut off their head in a dramatic sword fight, or some equally challenging task, often involving silver. Great if you're aiming for super-powered characters who walk on walls or shoot lightning bolts from their forepaws, but could create problems for low-key stories. A little more far-fetched than "elven years," but not much--by the time human genetic engineering makes shifting possible in the 2740s, we could already have cured old age.
Oh, and, Outwarddoodles:
First, what did I say about grammer?
And what I said, no. I think a werewolf would just be a healthy human, such as my grandpa. They get healthy romps around the woods for exercise, and with a bonus of some extra regeneration. But I just don't want to over exagerate how healthy a werewolf would be.
It's spelled "grammar." "Exaggerate" has two 'g's, and should be hyphenated with "over." (Sorry, but you left yourself wide open.)
Grammar officer: "Nothing to see; move along!"
Obi Wan: These aren't the verbs you're looking for...
Officer: "These aren't the verbs we're looking for... No, wait, I mean, these aren't the verbs for which we're looking...
Taking a Gestalt approach, since it's the "in" thing...