On the contrary, 150 itself seems to be middle aged for a wizard or witch. Armando Dippet, the former Headmaster, lived to be 355. He was older than the Ministry and died during canon, and that's without any elixir of life shenanigans. Aging and populations are just really inconsistently handled. There should be legions of magic users older than Dumbledore.

 

My personal preference on the issue is that abnormally long lifespan is simply yet another (if a bit more common) innate magical ability like being a metamorphmagus or parselmouth. Most of the wizards would die of old age around the same age as normal muggles would, but because of the magical nature of their health-care they have some decades of healthy life more.

With this system you can at the same time explain why there are relatively many very old wizards, while at the same time almost no one seems to have living great-grandparents. And why the only "statistical" "canon" source, the Black family tree, has no individuals aged more than 90.

Of course this conflicts with the other statistical "canon" source, the prop newspaper article that claims wizards have a life expectancy of around 138 years. Yet another prop newspaper claims that the oldest living wizard was 755 years old, though that same article sets a lower bound of world wizard population at 30 million. And although it has news about the Gringotts robbery in PS, it's dated at 2001...

In summary, there's nothing about normal age of wizards in the books (not even confirmed age for any of the main adult characters), and loads of wildly conflicting extended-universe information. Basically you can set your mind on whatever you like, and no one can claim you're wrong.

 

It does seem strange that wizards end up as decrepit as Dumbledore by what is effectively middle age. Dippet would have had nearly 200 years of wrinkles, old man smell and frequent urination by that metric. I thought it was only muggle medicine that let the elderly linger on without meaningfully improving their quality of life?

 

I wouldn't exactly call Dumbledore decrepit. Sure he's got wrinkles and white hair, but he moves pretty quickly when he wants to.

 

Uh - there are extremely few examples of witches and wizards reaching that age, that's one thing, and we don't know if Professor Dippet used magic to extend his own life. Don't mean he necessarily had to use an Elixir of Life, though. During the brewing of the Polyjuice Potion, one will obtain the elixir of Primum ens Melissae, which can rejuvenate, to some degree, the well-being and vitality of one's body by attracting and concentrating the source of spirit and soul found in some herbs. Take that, and add a regular intake of Magi-Me-More, and I see no reason a wizard could live to a ripe old age.
--- Post automerged ---

OMG! Rowling predicted Harry Potter RPGs on the internet! Captain Conspiracy, away!

 

Sure, I'm not disputing the fact that there are wizards who are more than 150 years old. But I don't see any evidence in any of the canon that living that long would be the expected norm: the society we see through Harry's eyes is very much of the same general age as in the real world.

What we see in canon is that it's entirely normal for wizards to have kids in their twenties, and with a 150 year life expectancy you would expect each and every family to have at least five generations alive at the same time. But yet there's no Potter great grandparents alive, no mention of any other great grandparents, and pretty much all top positions in the ministry we know of are held by people one or two generations older than Harry (Arthur Weasley, Amelia Bones, Marietta Edgecombe's mother, Crouch sr, ....), and someone as young as Percy can rise to somewhat high positions right after finishing school.

True, there might be some kind of retirement colony full of old wizards, but they sure don't show themselves in canon.

 

Plus there are explicit statements by JKR. E.g.

http://www.accio-quote.org/articles/2000/1000-scholastic-chat.htm

Of course JKR later revised Dumbledore's age downwards to 120, but there's no reason to think she went back on the general idea of higher wizarding life expectancy, or the idea that 70 is "sprightly" for a wizard. Especially as she continued to introduce old wizards like Marchbanks and Bagshot, and considering the fact that 120 is still well in excess of normal Muggle life expectancy, and at that age Dumbledore still appears to be decades away from death by natural causes: physically, there's no frailty to him, and his reaction times are still lightning fast. Dumbledore at 120 seems to be equivalent to a very healthy 65 year old.

The reason why we never encounter many very old wizards is fairly simple: the story is set in a school. The vast majority of the cast is made up of teachers, kids, and immediate family of close friends. I don't think I've met the grandparents of any of my friends. It doesn't mean they don't exist.

 

It's worth noting that the shorter lifespans of the Black family could well be due to other causes, like bad genetics (potentially caused by inbreeding?), illnesses and violence. Tellingly, almost all of the Blacks that we do know died well before their time.

It is also worth remembering that J.K.R. is notoriously horrible at maths and it shouldn't surprise us that she has made some inconsistent statements. It is probably best for us to assume somewhere in the middle of the two extremes we see: that wizards do have significantly longer natural lifespans than Muggles, but that extremes like 200-300 years or more are, at best, very rare; perhaps the equivalent of a Muggle living to the age of 110+.

 

You are also failing to factor in how the "parent generation" of Harry's formative years, as Molly said in the seventh book, eloped and ran off to marry as quickly as possible because they feared they might be "dead tomorrow" because of Voldemort's activities during the mid-1960's and outright warfare on the Ministry in the 1970's, so just because the parents of Harry and many of his classmates became parents in their early twenties, that don't necessarily hold true for most.

Also - I think many elderly witches and wizards might be prone to die from Dragon Pox. Like the parents of James Potter, the parents of Tina and Queenie, Abraxas Malfoy, former Minister for Magic Eldritch Diggory (who I don't think was even that old?), etc...

 

That is a possible explanation. However, I seem to recall a statement from JKR saying that magic apparently "cancels out" the effects of inbreeding to some degree? The Harry Potter Wiki has no sources on the topic, though, so maybe that was part of @Taure’s headcanon.

 

That's possible, within reason. Mind you, the Gaunts pose a counterexample to that theory.

 

Bullshit theories time.

It's all about the soul. The soul is connected to the body (as we can see with the effects of creating horcruxes) so why not assume that it's also important in those cases.

Philosopher's Stone works by strengthening the soul which in result strengthen's the body. Without it bumping the limit of longevity, the no-longer-user dies. No need to think about cell damage and other mundane things.

Similarly, if the body and soul are connected, then extensive magical changes to your look may:
Theory A: create dissonance between your body and soul, leading to various negative effects.
Theory B: affect your soul.
As those wouldn't be desirable and is hard to say what is extensive wizards would avoid changing their look.