In the first campaign I ran when 3rd edition came out, one of the principle NPCs was a 4-year old girl who had lost her parents to an orc raid. One of my players suggested I run a game that showed her as an adult. I advanced the timeline 15 years, and she became a PC. The campaign was great.
Since then, I've made a habit out of periodically jumping the timeline forward. Not only does it help keep the power level reasonable (as old heroes retire or die, creating a need for new heroes), but it lets the players see the long-term effects of their characters' adventures. My players have gotten a feeling of ownership about the setting, since their characters often go on to become local rulers and legends of the land, shaping the world in ways that I hadn't forseen. I highly recommend that style of play; it's quite fun.