I asked Eero about refreshments of Motivation pool on email, but I think is so awesome and useful, so I'm putting it here.

> I'm starting to use your idea from Solar System, where you are describe
> motivation pool for secondary characters. But I don't know when to
> refresh their pools.

My NPCs usually refresh arbitrarily off-camera. If they're refreshing with
PCs, then any type of refreshment counts for their one Pool. Otherwise the
NPC usually gets a full Pool when he comes back, assuming he's had
sufficient fictional time to recuperate off-camera.

> Also, in TSoY you have Tree-Corner magic and spells such as pool
> changing. How would you manage that, when Player Character would
> use it against npc?

I would remember that the one-Pool thing is a simplification for my own
comfort - I can always split the Pool into three on the flight if a
mechanical situation requires me to do that for some reason. In this case
add one point to each Pool when you split. I've never retained the split
Pools once the scene is over, though; the NPC goes back to simplified Pool
accounting whenever the situation requiring split Pools ends.

When I don't strictly need to have several Pools, I just have all Pool
effects target the one Pool; it effectively counts as every Pool a
character has all at once. Thus a "Drain Vigor" spell will just drain the
one Pool non-selectively with me (leaving one special point representing
the other Pools for later if the NPC gets a chance to do something
non-Vigorous), while for a "swap Vigor with Instinct" spell I suppose I'd
have to give the target split Pools for the duration make the spell
matter. Even then I might just ignore that part of the spell (assuming
there was some other, more important effect to the spell).

A third thing you can do is to keep the one Pool even when several Pools
should be involved, but add or deduct points from it to reflect the effect
of whatever it is that the characters are doing. For example, you might
decide that if a PC wizard is swapping the Instinct and Vigor of a NPC to
be helpful and give them more points in a Pool they need, you might just
add 3 points to his Pool to reflect the newly relevant reserves. Similarly
if the player wants to fuck with the NPC you might deduct points.

The important thing is that the simplified NPC accounting is there just to
simplify my life as SG; it's technically not rules, but rather just a
shortcut. If a situation comes up where it suddenly starts to matter what
sort of system I use, I can always open the character write-up a bit more
and make it more akin to a full player character's. This should be rare
basically because usually the NPCs are not that important; if a player
constantly cares a lot about how you're accounting for the NPCs, then
something strange might be going on.

Thanks again Eero!