From what I've heard, EA's as much of an Endurance hog as Dark Armor. Pair that with an End-hungry primary and you'll run out a lot. Nemu's right, though; End Drain makes a difference.
Another trick is you want to go digging for endurance recovery procs; the Performance Shifter proc and the Panacea health/end proc will go a long ways toward managing your troubles. More than that IOs you replace will do for you, even. Yes, they'll be expensive. Believe me, though, they're worth it.