I just bought the core, so I'm fairly new to the game. Played my first real game today, and I am confused on a point. A search through the available materials (and the net) didn't reveal the answer.

The quest cards (in the core at least) indicate that resources are placed on them at the beginning of your turn so long as a unit is questing on that card. However, the card does not state that those resources are spent when the quest's ability is used. Are these resources spent to trigger the ability? Or do they just keep piling on?

I assumed they're spent, since there seemed little point to continue piling them on otherwise. Also, we rather quickly were running out of the resource tokens in the unused pool until we switched to spending the tokens off of the cards.

Thanks!

You only put tokens on a quest while a unit is questing there. Most of the core set quest cards require you to sacrifice the questing unit to use the effect. When there is no unit on a quest, whether it left play or was moved, all tokens are removed from the quest and returned to the general supply.

As for the two quests that don't require the sacrifice of the unit: for Infiltrate! the amount of tokens on it matters, so you should keep track, but with Defend the Border you can just stop putting tokens on it once it has three. More won't make a difference, as there's no way for you yet to remove just some of the tokens.