Wow...
So much intelligent commentary! I will do my solemn best to respond in kind.
MavrickWeirdo:
I used CR years to keep everything standardized, and so I could throw in "harsh years". Yours (365 XP per year) is definitely simpler, however.
Tonguez:
I would define a scenario as: an adventurous event that we roleplay out (such as "The Delving of the Lost Castle of Carne"); a major subplot of the story arc (foiling the King's assassins); a year at a difficult job (farming, coastal fishing); a month at an exceptionally dangerous job (deep sea fishing, participating not on the front lines of a month-long battle); a full day of an insanely dangerous job (fighting on the front lines of a battle, delving the Paris sewers to clear out a goblinoid infestation).
I'd also give XP for special stuff, like completing a pilgrimage to the Holy Land for a priest character.
Regarding soldiers' rapid advancement on the front lines: in a typical full day battle, the soldiers who are thrown into the meat grinder up at the front will have
earned that XP and then some... if they've survived that long. And, of course, some battles will be easier than others (CR 1 or even 1/2).
Also, a soldier will generally spend, at most, a day or two on the front lines in the course of a week of battling, and once they reach veteran status (2nd or 3rd level) they won't spend much time on the front lines at all.
CRG:
Hey, that's pretty cool!

Sean's peasants advance a little fast for my tastes, though. Between the advancement and the aging, I want the majority of peasants to be 4th and under.
Celebrim:
I
really like the idea of sheltered living! I'll take that, please.
Regarding more thorough aging: I had to keep it somewhat simple for it to be acceptable to the players. Otherwise, I'd probably do something like this:
Aristocrat: +1 to CON for aging rolls.
Middle Class: no effect (merchants, sages, craftsmen).
Serf/Commoner: -1 to CON for aging rolls.
Urban Setting: no effect.
Rural/Wilderness Setting: -1 to CON for aging rolls.
Malnutrition: Each season of a year you spend malnourished counts as a full extra year of aging.
I will eventually have additional stuff for illness, typical death rate for peasants, and the like.
Blind & Deaf: These options are
chosen, not rolled, and I won't be choosing these two very often for NPCs. The most common ones are actually physical and mental disabilities.
(Side note: I'm encouraging the players, when they get a physical disability, to tie it into their wounds, scarring, etc. For example, "DEX -2; limps badly ever since that ogre crushed her legs with a boulder.")
Duncan Haldane:
Firstly, yes, a race that lives a long time will tend to reach higher levels. This is fine for my campaign (all humans, see
Europ races for details). For a more standard D&D3e campaign, I'd suggest either (a) increasing the time spans required for the elder races to gain XP (elves treat a 4 year period as a CR 2 scenario) or (b) dealing with the fact that longevity is powerful in your campaign setting.
In my campaign, the sidhe typically
are very high levels, but they dwell in their own worlds under hills and around unseen corners. Taking on a sidhe and living to tell the tale is worthy of legends.
hong:
Yes. I don't foresee many peasants beyond 5th level, either. The hypothetical 6th level peasant would have made it through 12 CON checks and -2 to all physical attributes, and a number of illnesses, bad winters and whatnot. He could exist, but he's a grizzled Commoner who's dealt with wolves, bandits, and the King's Men over the course of four decades of life. And he's reknown locally, as he should be.