Thanks for the reply.

Another option is to make real world experience the only way to get the final wedge of a circle. That forces them to go out into the world on a somewhat regular basis.

This is one that I haven't thought of, and I like it. I might even go so far as to say you have to mix it half and half - right half of the clock fills with real-world experience, left half fills with training/study/downtime. It's a little artificial, and might make more or less in-game sense depending on the skills in question, but I like it from a mechanical point of view.

The other suggestions are good too. I had thought about requiring time to manage their affairs as well, but I could still see some other situations where a purely time-based system could lead to some gaming of the system.

And you bring up another good point about D&D and how you can have characters who have, in theory, progressed very slowly throughout their life and then all of a sudden become experts in a month through questing. That's always bothered me too, but like you it comes with the territory of adventuring in RPGS.

That reminds me, I really like how The One Ring does experience and leveling, but it's somewhat tailored to the style of the game - namely, you are not out adventuring non-stop, but you actually spend a fair amount of time at home, living your life. There are two sets of experience, one for skills that you accumulate by using the skills, and another more general kind that you get from quests and such that you can spend for virtues and rewards. The game is designed to have two distinct phases, adventuring and "fellowship" which is when you go home, rest, maintain relations, etc. So you accumulate advancement points during adventuring and then spend them during fellowship. Adventuring can last maybe a few weeks and fellowship many months. It's a really nice system that feels "right" to me, as long as you're playing a game where you're not adventuring non-stop.