Level-up Learning (and Forgetting)

In ICE, and some similar systems, you have a chance to raise your skills without spending XP via use. This variant is intended for use with d% skill-based systems.

If you use a skill you put a tick next to it, and can do so several times (max 3 or 5 ticks, say). When you level up, roll d%. If you roll under the skill add a level to it (1 point, 5 points, whatever it is). If you have two ticks add 5 (to the roll-under target), and if you have 2 ticks add 10 (etc.).

This way you have two factors to improvement: low skills get raised faster, and skills you use often raise faster.

There are plenty of caveats or changes to make at preference: can't raise skills over 50 this way; only get ticks for failures; must make an attempt at a 'hard' challenge at least to get a tick, etc. Whatever, they all serve a purpose but don't change the mechanics that much.

You can also let skills atrophy. If you have a skill where you've got points in it and have no ticks since your last level-up, roll on that one as well. If you roll under you lose a step (1 point, 5 points, etc.). This makes it more likely that you lose your edge with your 90% skills if you don't put in a bit of upkeep effort.