Levels or skills should advance when they are used, but Basic roleplaying (Runequest, Call of Cthulhu, Stormbringer, etc.) makes it awfully slow, while Burning Wheel’s approach requires inelegant tables and book-keeping and system mastery.
The idea is: For each class or skill write a list of fictional actions.
So, for fighter in old school game:
- Fight a superior foe
- Fight against superior numbers
- Protect an ally in combat
- Avenge someone close to you (kill the orcs who burned your father’s farm, say)
- Recover an ancestral weapon or piece of armour
- Use an ancestral weapon or piece of armour
- Recover a weapon or piece of armour of legendary status
- Use legendary equipment
- Slay a beast of legend
- Lead an army
- Survive a siege
- Be the master of a company of mercenaries
- Conquer a castle
- Establish a stronghold
- Keep a stronghold
Whenever an action is accomplished, mark it.
Once you have marks equal to next level or rank, erase all marks and increase the level or rank by one.
Note that the list includes things that fighters do, and likewise people who do those things are fighters, to some extent at least. At low leves fighter only need to fulfill their role in the party, while at high levels they need to build a legend of their own and influence the world in order to advance.
As a further bonus, this gives a nice way of estimating NPC strength. See how many things you mark, and that is an upper bound for their level. How many things they certainly have marked at the same time? That’s the lower bound. Lord of a castle in an area of constant warfare certainly has led an army, survived a siege and kept a stronghold at the same time (so level at least three), but may also have conquered a castle, led mercenaries, protected an ally in combat, fought against superior numbers and against a superior foe and avenged someone close (so at most level nine).
It is easy to change the conditions and at the same time change what fighters are in the setting, and who are fighters in the setting.
For further complexity, training: Obviously it could be yet another action. But maybe it is automatically erased when the character stops training. Otherwise, better action would be to train under famous/more skilled/legendary master.
Or consider: Add some actions that depend on character race or alignment.
Or: Have players build the list when starting play, or adding a new entry at the beginning of each session, or when someone levels up that class or skill.
There’s some limitations, of course. You would not want to do this in a game system with huge list of skills, or then you would have to have each character only develop a handful at a time.
Skill reduction can be handled like this, too. Write one action, or several actions, or absences of actions. When they are marked, the player has the option of reducing the skill or class level in question. If the players opts to do so, then they get some compensation equal to the marked actions and the marks are erased. Some tokens, say.
Similar rules: Magical items in Earthdawn (IIRC), keys in Solar system (the reduction is buy-off), this thread about Dungeon world.
In other news
I’m running two Amber games at Tracon (if there are players – last year it was an anime convention with some roleplayers huddling in a corner) and maybe giving away some rpg and maybe fantasy books I no longer use.
There has been several updates and one playtest of diceless/nopaton, which now lives on Google docs. It is still in Finnish. The major change is that now there are some principles for playing it. And there is rotating player (and hence game masters, sort of).