We’ve all played plenty of systems with rules for aging, but hoSw many of us have played a campaign where enough time passed that it was relevant? How many of us have played games where the time between dungeon crawls has been measured in days, not weeks? I don’t know about you, but I’d fear for the mental wellbeing of people delving the depths of antediluvian dungeons as often as you or I go to work. Are these people sentient, living creatures with psychologies or are they combinations of stats and classes that can face undead horrors five times a week without breaking a sweat?
So after three paragraphs, where am I going with this? Downtime. When the dungeon is clear, when the big bad evil guy is dead and the players return to town, work in some downtime for the characters to be human (or dwarven, or orcish). Even though you may be playing next week that doesn’t mean a short period of time has to have taken place for the characters. Maybe they freed the town from enslavement by the devilish mayor and the player characters settled down. Maybe a year or two has passed. That player who was constantly trying to get his fighter laid, well maybe there’s a couple newborns in town with his strong chin. Maybe the dwarven crafting character got a chance to open her own shop in town. Maybe the mage has an apprentice. Hell, maybe the party bard is the new mayor. This serves two purposes; the player characters become characters more than blocks of stats and it connects them intimately to locations in the world, giving them reasons to fight and giving you, as a GM, things to threaten to force them into action. Why should the party go clear a goblinoid cave near town? Because one of those strong-chinned newborns is missing and someone saw a bugbear in town last night.
French Impressionist composer Claude Debussy once said “music is the silence between the notes.” If you’ll allow me to make a wildly hamfisted comparison, character is the time between playing. What makes a character a character and not a pair of pants is what that character does when you’re not in direct control. What makes that character human (or gnomish, or halfling) is that they have desires and motivation shaped by, but separate from, those of the player. And, ultimately, what will make them feel more alive is the slow march toward a death by old age, though they’re bound to get eaten by a dragon along the way.