Green - Not the New Purple.

The common refrain on the release of the Burning Crusade was 'Green is the new Purple'. Quested and BoE uncommon and rare items from the very first few quests in Hellfire Peninsula were better than a huge number of Epics from end-game Vanilla WoW. Part of this was the reduced cost of stamina in TBC items which wasn't retroactively changed in vanilla Epics, and the highly specialised nature of most post-BWL gear didn't help either. But for whatever reason upgrades came thick and fast for the majority of players, even those who ground out Epic Honour Gear in 1.12.

Baring a very significant change to itemisation in the next few weeks the same will not be true in Wrath of the Lich King. The itemisation formulae have remained pretty much the same so there is no new slack in the budget for higher stats or DPS. Hence just as you wouldn't expect lvl70 TBC Greens and Blues to replace Heroic Gear you shouldn't expect lvl70 WotLK Greens to replace Heroic Gear.

There are certain exceptions, for instance if you are changing your spec from an end-game tanking or healing spec and haven't been able to pick up much DPS gear. Also your character's mechanics may well have changed to make better use stats you previously didn't collect, such as Crit for DoT classes or Haste for Ret Paladins. Hence it pays to at least give the quest rewards you can achieve the once over, but don't expect to see much worth more than the gold resale value. This is especially true for Trinkets and Relics, where historically itemisations hasn't been too good or they've been difficult to get (damn you Shard of Contempt!).

Whilst levelling in the Beta I've found that a good rule of thumb is expecting to find upgrades from rare drops at lvl70 plus your Epics' Tier. Original Badge gear and Kara Epics are around Tier4 and the epics released with the Sunwell are Tier 6.5, so expect to see upgrades starting from lvl74 group quests and dungeon drops.

You can stave off upgrading for another few levels by swapping your gems. Honour gems are no longer BoP or Unique-Equipped and the item budget value of the socket is often calculated as if a rare gem were socketed. Rare levelling gear tends not to have many sockets, so slotting in an Epic PvP gem over a rare one can extend the life of Badge or Tier gear by another level or two. Equally picking up some of the new uncommon crafted gems, which have received an appreciable boost to levels equivalent to that of the TBC Epics, can serve to stave off the inevitable.

So, don't be afraid to spend time in Kara or Heroics and invest those Badges on gear rather than Nethers or Vortexes. They'll see you in good stead for a few levels yet, especially the Sunwell Badge gear.