As far as point three, this is a serious concern for adventurers. In 5e,characters can only have three magic items attuned at a time(DMG pg 138). Therefore, unlike 4e, the number of magic item slots available to characters are very limited and magic items must be carefully considered. Na...
Whenever you make an Intelligence (History) check related to magic items, alchemical objects, or technological devices, you can add twice your proficiency bonus, instead of any proficiency bonus you normally apply. You know the Mending and Prestidigitation cantrips. Tinker. You have proficiency ...
Identify (Bard, Wizard) lets you learn the properties of magic items (so you can use them). Shield (Sorcerer, Wizard) gives you +5 to your armor class for 1 round as a reaction. Shield of Faith (Cleric) gives you +2 to your armor class for up to 10 minutes. Which classes get th...