I'm in seasonal internet quasi-hermitdom, but I'm peeking out to ask this question: what doubles or triples when a character's skill in operating a magical device exceeds level one?
Two things prompt me to ask this question. Firstly, the time factors of many devices are either instant or non-existent (i.e., the skill check is merely a game mechanic for bias purposes), and the durations are sometimes dictated strictly by device type ("always active," "when worn/held," etc.). Those are usually the top two candidates for doubling and tripling. It's easy enough to turn to area or whatever RS controls, but that brings me to the second sticky point: Device creation rules specify sit-mods that allow the creator to create a device that will "operate at a skill level of two or three." If the device creator controls the potency of the spell effect, what's left for the device user?
Two answers occur to me. The first is that there is no bonus for the character who achieves a 2@ or 3@ SAL in operating an Always Active or When Worn/Held device beyond the increased percentage chance of its operation in low-bias worlds. That's consistent with the printed rules and justifies the efforts of powerful device creators, but it seems poor compensation for the player who devised a double-doubled or triple-tripled training program for such a skill.
The second answer is, perhaps the potency of the skill effect is controlled by the higher of either the user's skill or the potency inherent in the device from its creation. This rewards the efforts of the training player, but it saps some of the value from creating inherently powerful devices.
A third answer is to allow both creator and user to contribute multiples, but surely that's imbalanced. Isn't it?
Generally I look for whatever can be doubled or tripled effectively. There are quite a lot of devices for which repeat factor (wands) or duration (potions) can be doubled or tripled. If that's not possible, I look elsewhere.
And I think that the skill ability level increase in the device creation is independent of the skill ability increase for the device user, in the same way that martial arts maneuvers pay a price for increased damage but the skill ability level and strike values can still increase the damage. (Note that weapons are specifically excluded from this, receiving damage category bonuses instead of increased base damage levels--but even so, the damage category bonuses for SAL still apply, being converted to points if not countered by damage category penalties.) Thus if I've created a wand of fire missiles which works as if a third level SAL cast the spell, that means effectively that the rate maybe the range have been tripled and I'm at +2DC; but if I learn to use it with a 3@ SAL, I triple that rate and range again and get +DC+points (because I'm targeting, so my other +DC has to come from my strike value).
I think the point on the magic device creation is that one way to spend the points accrued in the ritual is to increase the power of the device as if it were the same skill used by a higher level user. Since you can achieve faster rate, greater damage, longer range, and any other such affect directly by spending points, this amounts to a shortcut for doing the same, which might get more results (possibly with some limitations, e.g., the damage category bonus limitation) more cheaply.
Also, in general I work with players to decide what is doubled or tripled when they reach the next level on a skill.
--M. J. Young