Well, generally you'd let AutoEquip do that for you, but it's kind of screwy right now since it's not completely working (unless I'm wrong and they've finally gotten it working in this release), but otherwise you'd just have to update your gear by hand every few levels. I'd say every 5-10 levels.
because I tried a rogue but it he was dying way too much now I'm trying a Paladin and he's dying but not as much.