This guide is meant to give a general overview for Energizements and how to optimally roll them (based on my, Marlex, experience).
When rolling Energizements you can roll Energizements of the same Tier or 1 Tier lower. (Detailed Info about the mechanic here) Ideally you want 3 desirable Energizements of the same Tier as the item you're rolling on. However that often means you'll have to lock 2 Energizements and reroll the 3rd for 40 energizement shards, which can become quite expensive. For that reason I strongly recommend going for 2 good rolls of the same Tier as the item and just taking whatever for the 3rd (with few exceptions which you should immediately reroll, see below) After getting 2 “perfect” rolls on each piece you can go for the 3rd, I recommend moving on to a different piece even if you roll the desired Energizement 1 Tier lower. When you have done that for each piece, and it's not time for you to move to the next Equipment set, you can finally try to get the perfect 3rd roll.
Tier 1-3
Just unlock 3 Energizements, maybe roll a couple times without locking.
Energizements help, but aren't super important at this stage of the game.
Tier 4-6
Those tiers still go by fast so don't worry too much about getting 3 perfect rolls.
Two good rolls on each piece will get you far. Min/Maxing is probably not worth it, yet.
Tier 7-8
2 perfect rolls and 1 good but lower tier roll is still fine.
Tier 9+
You can aim for perfection.
Slot: Mainhand, Sidearm, Arm-Augment
Together with IDR best in slot.
Early game Damage will be stronger, mid to endgame as enemies gain more Damage Reduction and Compendium provides a decent amount of damage,
IDR will gain more importance. Still damage energizements shouldn't be neglected.
Slot: Mainhand, Sidearm, Gloves, (T9)Brain-Augment
Ignore Damage Reduction is together with damage best in slot.
Due to the IDR Formula each additional source of IDR will add less and less to your total IDR.
However since late game monsters gain a lot of DR, it's worth it.
The value of the rolls on Brain-Augment is very small, it's better to roll some other stat on Brain.
Slot: Legpiece, Boots
This is generally best in slot up to T9, which is when you start reaching Attack Speed Cap (10) even without energizements.
Each time your Attackspeed goes up will be a big boost to your strength, sometimes allowing you to defeat monsters before they even have the chance to hit back.
This is especially noticable in low/mid tier incursions where your killcount will make a huge leap if you manage to 1hit KO the enemy without taking damage, since
Incursion monsters do not gain multikill buff and will not get faster during the fight.
Sometimes adding a Speed energizement won't push you into the next Attack Speed Tier, in which case it might be more benefitial to keep another energizement.
Slot: Any
Can't go wrong with this. Very good.
Slot specific energizements takes priority, though.
Slot: Chestpiece
Best in slot, no competition.
Slot: Any
Pierce is a direct multiplier to your damage, if you have too little the enemies armor will reduce your damage.
Generally you want a good amount of pierce, bare minimum it should be equal to enemy armor.
Keep in mind that enemies armor gets higher with multikill buff.
The true dmg is just a níce bonus.
Slot: Gloves
This is an option if you have low base pierce, but generally you'd prefer IDR on gloves.
For later levels it seems roughly equal with IDR and pierce will give a slight edge in the Spire,
especially with the right Spire Modifiers
Slot: Any
This is a bad energizement and should be rolled over.
At low combat levels it won't provide alot of base stats, at high combat level it's already dwarfed by the base stats your equipment provides.
Except maybe very early game the % Energizement is strictly better.
Spire: With the right combination of Spire Modifiers this is actually BiS for beating the Spire.
Slot: Any
Good all around. Savagery and Fortitude are the foundation for your combat strength.
Fortitude scales very well with the Health Multiplier itself provides, aswell as Colossus (corp buff) and Juggernaut injections,
as such it's a higher value Stat compared to Savagery.
Though in some scenarios a “glass cannon” build can achieve good results,
but once the enemies Attackspeed scales passt the limit of 10 Attackspeed placed on the Player, they'll fall apart.
T10 Monsters have Agony, which allows them to deal Damage based on your max Health.
Therefore a damage focused build is recommended for the transition between T9 and T10 until you gain enough agony resistance.
Slot: Shoulder, Earrings
Since the stat-rework there seems to be no scenario where it is good picking Min Damage over other Energizements.
Only reason would be if you want to reduce randomness.
Slot: Shoulder, Belt
Not a good Energizement, just get more Savagery or Pierce.
Slot: Ear-Augment
Get some Fortitude or Armor instead.
Might be usefull in Spire with the right Modifiers, but generally not needed.