What Is The Optimal Amount Of Life Steal For A Sustainable Build?

Just as title says but I've seen tons of builds that have sustainability with life steal as low as 440/4 to about 1200/4. Any answers?

 

It depends. If it's your main sustain on a melee build, I'd want closer to 1200, but if you've also got health regen, heal spells, totems or potions, it would be less important. Also if you're a spell build it won't be quite as important since you're not going to get quite as close and take as much damage probably. Obviously tanky builds will get more benefit from a small amount than a glassy build (due to the amount of ehp recovered).