Guidance is for any check. A check to defeat, a check to acquire, a check to recharge, a check directed by anything. If you are attempting a check, then someone can play Guidance to add 1 to your result.
The cards that have the recharge box on them are a type of card that after playing it by following the directions in the Powers section of the card, you might be able to Recharge it instead of what you were directed to do by the Powers section. It is common on spells, items, and blessings.
Recharge: This explains circumstances under which you may recharge the card—put it on the bottom of your deck—after playing it; it usually appears on cards that you would otherwise be required to discard.
Usually, recharging requires a skill check; if you don’t have at least one of the skills listed for the check, you cannot attempt to recharge the card. If, while attempting another check, you play a boon that you may be able to recharge, resolve the current check before attempting to recharge the card. The boon is in play (and does not count as being in your hand, in your deck,in your discard pile, or elsewhere) during the intervening time. (This check applies only after you have played a card—when a card’s power directs you to recharge it as part of playing it, and does not specify a check, you don’t have to attempt a check to recharge it.) You cannot recharge a card you are forced to discard, or one that you choose to discard as part of taking damage or resetting your hand at the end of your turn.
So if a card's power section tells you to recharge it to activate that power, then you don't need to worry about the recharge box. And if the recharge box says "None" then there is no way to potentially recharge it. You just do with it what the Powers told you to do.
Not a silly question at all. Because you have to recharge it to play it.
Each boon's power consists of a "cost" (do this with the card) and a "benefit" (so that you can do this). The recharge box, when it doesn't say None, gives you a condition that you might reduce the cost. But it is never guaranteed. The condition has to be met first.
Look at Thieves Tools and Masterwork Tools.
Powers
Reveal this card to add 1 die to your Disable check.
Discard this card to defeat a barrier whose highest difficulty to defeat is 11 or lower.
Recharge
Succeed at a Disable 8 check to recharge this card instead of discarding it.
PowersReveal this card to add 2 dice to your Disable check.
Recharge this card to defeat a barrier whose highest difficulty to defeat is 14 or lower.
Recharge
None
The second option under the Powers of each are very similar. But the cost for the Thieves' Tools is higher, discarding it vs. recharging it. The Recharge box on Thieves Tools creates a possibility of recharging it. But you are NOT guaranteed to succeed at the Disable 8 check. You might, but you might not. Especially depending on what skills your character has.
On the Masterwork Tools, you recharge it to activate the second power. There is no need for a recharge condition, because it is either revealed, and thus back in your hand, or recharged already.
And you are welcome. Glad to hear you are enjoying it. It is indeed quite enjoyable.
It would probably be clearer if the recharge box was actually labelled recharge check, as that is what it actually is. This would make the Amulet slightly more obvious, as there is no check to recharge it.
I think that would work for all the items and spells I can think of, but the recharge box also appears on blessings. In that case, the condition isn't dependent on a check, but on two cards being identical. I'd imagine they wanted the recharge box as general as possible to allow for things other than checks. Like maybe "Discard another card to recharge this card instead of discarding it." I'm just making that up, but there are potentially other possibilities.
Alternatively, they could've just removed that "Recharge" box entirely, and just put the appropriate recharge effect in the "Powers" box of each card when necessary. It would've opened up more white space in this section that could be used to describe more complicated effects.
It needs to be played prior. The order of attempting a check is:
Determine the die you are using.
Determine the difficulty
Play cards and use powers that affect the check (This is where you play Guidance)
Assemble the dice
Attempt the roll (This is where you add the +1 from the Guidance spell in, but you played it earlier. The rulebook says: "Roll the dice and add up their value, adding or subtracting any modifiers that apply to the check." You got that modifier from playing Guidance earlier.)
Take damage if you fail a check to defeat a monster
Luckstone is a card that lets you play it after you attempt the roll, if you failed. But it Luckstone says that specifically. So it overrides the rulebook on the normal order of when to play it. Guidance doesn't say anything about getting to override the rulebook order, so it has to be played before you assemble the dice.
Coincidentally, that order is also why you don't get to add your skill feat modifiers in when you play a blessing.
Determine the die you are using.
Determine the difficulty
Play cards and use powers that affect the check (This is where you play a blessing.)
Assemble the dice (This is where you grab the extra dice as directed by the blessing.)
Attempt the roll (This is where you add your skill feats into the result of what the dice add up to. So they don't get multiplied by the blessing.)
Take damage if you fail a check to defeat a monster