Hey quick question, I read the whole guide on ele damage and I think I understand it, but for example, if I had 12% lightning damage on my neck and I lose around 10% damage by wearing the neck, is it worth it? 3/4 of my damage spells do lightning damage.
Your question is very confuse, but if I've understood correctly you mean that you have a potential upgrade that makes you lose 10% on the tooltip, but it has 12% lightning dmg on it, and you also said that you have 3/4 skills that uses lightning.
Well you pretty much will do 10% less dmg on that single skill but you will also do 2% more (12% from the ele dmg -10% dmg lost) in the other 3 skills, seems pretty weak upgrade tbh.
But the question you have to ask yourself is losing 10% dmg on that skill worth the gain in 2% dmg on the other skills?
Let's say you do 100,000 damage with your spell, and you lose 10% DPS it makes it 90,000 - on THAT you gain 12%, so 100,800. It will be 0.8% more, not 2% more. Read the guide ;-)
In general a quick way to calculate it is (damage * (1-DPS loss) * 1+elemental damage gain); in that case it's ((x * (1-0.10)) * (1+0.12)) = (x*0.9*1.12) = x*1.008. In general this is a quick way to calculate it: 0.9*1.12 (just multiply the two factors after subtracting the first from 1 and adding the other to 1).