Question on Aid Another

[modicasolis]

I know Aid Another can be used to help on spell saves but is there a time limit on this Aid Another bonus? Like, if I aid an ally one round and then two rounds later, a caster fires off a Fireball, will they still have that bonus?

Part two of this question is, if so, can Aid Another bonuses of different types be in effect at the same time? Like if I aid an ally one round for his Attack but he doesn't attack and then I aid the same ally for his AC, will he retain the bonus for Attack and AC? Or does the second aid overwrite the first?

EDIT: Found the answer to the second question but the first still stands.

But it prompts another question. The rules say multiple people can aid an ally and that similar bonuses to stack, but if I can aid someone twice in one round, do they get both of those bonuses? With Swift Aid and a Standard Action to Aid Another, I could give a bonus to AC and Attack. Is this legal?

[modicasolis]

Any ideas on this?

[Xaratherus]

Just quoting this here, because to be honest I wasn't even aware of this line until I went searching to figure out what you were talking about regarding spell saves:

Combat - Aid Another wrote:

In melee combat, you can help a friend attack or defend by distracting or interfering with an opponent. If you're in position to make a melee attack on an opponent that is engaging a friend in melee combat, you can attempt to aid your friend as a standard action. You make an attack roll against AC 10. If you succeed, your friend gains either a +2 bonus on his next attack roll against that opponent or a +2 bonus to AC against that opponent's next attack (your choice), as long as that attack comes before the beginning of your next turn. Multiple characters can aid the same friend, and similar bonuses stack.

You can also use this standard action to help a friend in other ways, such as when he is affected by a spell, or to assist another character's skill check.

Personal opinion: The duration described for attack rolls and AC bonuses states that your ally's attack (or the attack against him) must come before the start of your next turn. The skills section doesn't explicitly say the same thing but the assumption is that when the character goes to make a skill check, you make a check at roughly the same time to try and assist.

Because of that, I'd say that you'd need to be able to spend your standard action the round before your ally goes to make the save in order to assist. But that is's just my interpretation (of a rule that I didn't know existed until now - and one that's frankly pretty vague at best).