I've been curious about this for some time, but-
If a character shape shifts into a creature with a longer lasting life (For arguments sake, Human -> Elf always came to mind), would they have the same life span, if they stayed persistently shifted?
As the entire physical body is transformed (Or so I have been told), Would not a Human turned Elf live for centuries if it never left the elf form?
Masters of the Wild, p. 69: Greater Wild Shape (Sp) Greater wild shape works like wild shape...
Player's Handbook, p. 37: Wild Shape (Su) This ability functions like the polymorph spell...Errata: Polymorph no longer exists. See: Alternate Form (Sp).
d20SRD: Alternate Form Except as described elsewhere, the creature retains all other game statistics of its original form, including (but not necessarily limited to) HD, hit points, skill ranks, feats, base attack bonus, and base save bonuses.Nowhere does it say the druid adopts the lifespan of her chosen form. At level 15 and 10 for druids and shifters, respectively, the character becomes immune to magical aging and will stop suffering more ability score penalties from aging, although any penalties already applied remain in place. The character will still die from old age. Even if this wasn't the case, the effect lasts for 1 hour per level.
Which is to say, 'No' - Otherwise all Mages would just polymorph into Sun Elves rather than try to be Liches and shit.