If the item's activation is subsumed in use and takes no extra time, use activation is usually not even an action. When an article of magic clothing, jewelry, or armor is discovered, most of the time size shouldn't be an issue. Many magic garments are made to be easily adjustable, or they adjust themselves magically to the wearer. As a rule, size should not keep overweight characters, characters of various genders, or characters of various kinds from using magic items. Another way to figure this number is to multiply the spell's level by 1.5 and add 10 to the result.
Magic items use the same saving throw bonus for all saves, no matter what the type.
The only exceptions to this are intelligent magic items, which make Will saves based on their own Wisdom scores. Magic items, unless otherwise noted, take damage as normal items of the same type. A damaged magic item continues to function, but if it is destroyed, all its magical power is lost. Many magic items offer a bonus on attack rolls, damage rolls, saving throws, Armor Class, ability scores, or skill checks. Skill check bonuses do not have a maximum.