How fast do NPCs earn experience?

[Errant]

Is there any accepted standard for how fast NPCs gain experience? Particularly for non-combat/non-adventuring type activities?

How long does it take a Commoner (Baker) to gain a level, baking bread & pastries day-in, day-out?

I was thinking 1 XP per GP earned from their regular Profession checks might work, but what about Craftsmen?

 

[Lord Ben]

Someone had a system where an NPC of X level would roll a die and if the die was higher then his level then he gained a level. You roll once per year.

So if you have a guy who's hired as a town guard and given training of War1, and he stays on for a year. After a year lets say you roll a d6, if you get higher then a 1 then he gained a level. Next year he has to gain higher then a 2 on the d6 roll. Now lets say he gets some "accelerated training" in the form of a whole lot of goblins in the area. You might choose to do a check every month as well to see if he gains. If levels are gained easier in this area of the world due to other circumstances then you might want to start rolling d20's, etc.

It's not too useful XP wise, but it's a decent system for figuring how often NPC's level up. Lets say your PC's have a backstory of the local sargent in a peaceful villiage that didn't like them and that was three years ago. If he was War2 then, you could roll a d6 for each year to find out what level he is now.

 

[Archer]

Just assign a level to the NPC when first created. It is unlikely in the span of a normal campaign for an ordinary NPC to advance. If a major character needs to advance in level then simply do so and justify it as backstory. If the character adventures with the party it gets a half share of experience and levels up normally.

 

[Errant]

Actually what I'm trying to figure out is a system to workout the proportions of levels in general D&D society &/or to workout how long (on average) a x-level NPC would have been practicing his/her profession/class.

I could use the Town Generation rules to work out proportions to some extent, but that doesn't help me in deciding how old the particular NPCs or how long they've been around.

I figure even a genius/prodigy wouldn't master a profession overnight, & dogged persistence will eventually pay off for less talented (but lucky enough to stay alive) individuals.

 

[hong]

Actually what I'm trying to figure out is a system to workout the proportions of levels in general D&D society &/or to workout how long (on average) a x-level NPC would have been practicing his/her profession/class.

I could use the Town Generation rules to work out proportions to some extent, but that doesn't help me in deciding how old the particular NPCs or how long they've been around.

I figure even a genius/prodigy wouldn't master a profession overnight, & dogged persistence will eventually pay off for less talented (but lucky enough to stay alive) individuals.

These aren't the sorts of questions that D&D is designed to answer. A GM with a simulationist bent is better off using a ruleset that caters to simulationist tastes, eg GURPS.

D&D works best when the PCs venture into the dungeon, kill the monsters, and take their treasure. Issues of world-building and so forth tend to be subordinated to that purpose -- ie, the world exists only to the extent that's necessary to support the PCs in their quest to kill the monsters and take their treasure.