Do items only take damage when specifically the target of an attack/ sunder attempt or spell or would an item worn or carried by a player caught in any area affecting attack like a fireball spell or in a dragons breath weapon also take damage?
The most relevant part of the rules for discribed situation is:
Unless the descriptive text for the spell specifies otherwise, all items carried or worn by a creature are assumed to survive a magical attack. If a creature rolls a natural 1 on its saving throw against the effect, however, an exposed item is harmed (if the attack can harm objects).
There are several things we gain here:
- While that text is a part of rules describing spells, term "magical attack" may wery well imply that at least magical attacks which are not spells (mostly supernatural) may be handled similarily. Spells obviously work this way (RAW - spells only). Spell-like abilities - almost certainly intended to work like spells. Extraordinary - who knows? Probably a DM call.
- All items in possession, magical or not, are handled equally. Possessor rolls 1 on his save - one (and only one) of them is affected, but may make it's own save. Otherwise they are "assumed to survive an attack"1, in other words are unaffected.
- Rule makes no difference between types of attacks. AoE, single- or multiple-targetted, ray or melee touch... if it allows a save and can in question harm objects, it is a sufficient attack.
1. There is actually second possible case when items are affected at this point. When the descriptive text for the spell (or probably the ability, see above) specifies that item/items, attended by the affected creature, are also affected/affected in adition. This situation is probably out of scope of this question.
Unattended non-magical items never make (always fail) saving throws (SRD, Carrying, Moving and Exploration). Unattended magical items make saves at 2+CL (Intelligent magic items modify this by Wisdom) (SRD, Magic Items). Attended non-magical items make saving throws as their attendant, and attended magic items save at their own base, or their attendant's, whichever is better. According to the Magic Overview, Attended items only need to make saves if they are exposed, and their attendant rolls a natural 1 on his save, and then only one randomly selected item must attempt a save.
So, if an attack can affect objects, then unattended non-magic items are always affected as if they failed their save, and 1 exposed attended item, selected at random, must only save if their attendant rolls a natural 1 on his save.
Interestingly, I find no references suggesting that a dragon's breath weapon affects objects (except for that of a rust dragon (Draconomicon (3.5e) pp186-187)), so no save appears to be needed against it. Dragons don't generally appear to destroy their loot unintentionally, it seems. Unless they tend to cast fireball.
Items only take damage when the damage source says they do.
For example, fire (but not fireball spells and the like):
Catching On Fire
Characters exposed to burning oil, bonfires, and noninstantaneous magic fires might find their clothes, hair, or equipment on fire. Spells with an instantaneous duration don’t normally set a character on fire, since the heat and flame from these come and go in a flash.
Those unlucky enough to have their clothes or equipment catch fire must make DC 15 Reflex saves for each item. Flammable items that fail take the same amount of damage as the character.
If there is risk of damage to items, then the worn or carried item gets the same saving throw as their wielder. (If it's unattended, it doesn't):
Nonmagical, unattended items never make saving throws. They are considered to have failed their saving throws, so they always are affected by spells. An item attended by a character (being grasped, touched, or worn) makes saving throws as the character (that is, using the character’s saving throw bonus).
Magic items get a save even if unattended:
Damaging Magic Items
A magic item doesn’t need to make a saving throw unless it is unattended, it is specifically targeted by the effect, or its wielder rolls a natural 1 on his save. Magic items should always get a saving throw against spells that might deal damage to them— even against attacks from which a nonmagical item would normally get no chance to save.