Life expectancy in the Potterverse and associated problems

[Ali]

No: HPFGUIDX 81248

JKR has told us that wizards have longer life expectancy than 
Muggles: http://www.the-leaky-
cauldron.org/quickquotes/articles/2001/0301-comicrelief-staff.htm

This surely gives legitimacy to some of the Pure Blood aversion to 
marrying Muggles, although not for the reasons given. Quite simply, 
if an average wizard lives to 150 (wars, terrorism and general WW 
living notwithstanding), and Muggles live to 75, then that would 
surely lead to many broken hearted Wizards when they're yet to reach 
middle age. It also means that whilst they are still young, by their 
standards, their partners are nearing the end of their lives. As 
different age groups tend to have different outlooks on life and be 
at different stages of the reproductive cycle, this could impose 
huge strains both physically and psychologically on partnerships.

Does a Muggle-born Witch or Wizard have a longer life span merely 
because they are magical, or do they too die earlier? If this is the 
case, what would the life expectancy of a Half blood like Harry be – 
assuming that they die of old age?

Given that a squib has some magical attributes, do they have a life 
expectancy as long as the average wizard, or lacking in magical 
blood, do they live and die like Muggles? Filch seems to have a long 
history and look to the good old days, so perhaps this is indicative 
of squibs having wizard-like life expectancies?

Perhaps, wizards have a longer life expectancy only because they 
indulge in some kind of potion-taking which has an effect similar to 
the Philosopher's Stone? JKR has told us that wizarding life 
expectancy is longer. She has told us Dumbledore's, McGonagall's and 
Snape's. But from that, we are still left to extrapolate what the 
life expectancy actually is.

I still find it curious that Lucius Malfoy has so much power at the 
age of *only* 41 if many wizards to reach 150. The WW strikes me as 
very traditional, and thus unlikely to look too kindly to *young* 
upstarts like Malfoy, even if they have impeccable Pure-Blood 
credentials. 

Why is McGonagall lucky to have survived the stunners in OoP "at her 
age" (p. 644 OoP UK edition) if she is only half way through her 
life? Surely, she would have been lucky to survive. End of story? If 
a 40 year old in Muggle Britain survived an horrendous accident, 
they would be said to be fortunate, not because of their age, but 
because of the accident. Is this an inconsistency? 

Dumbledore isn't the only very old wizard as Professor Marchbanks 
tested him in his NEWTS, indicating that she is at least a few years 
his senior (p. 627 OoP UK edition).

I suspect that the issue of Life expectancy is yet another potential 
inconsistency in the Potterverse, and one about which there has been 
curiously little discussion.

Ali