resistance armors: All 5 would be best but not necassary before going to abyss(Level115+). We would suggest getting them all. Some monsters may deal dual damage types so people that say oh it doesn't matter what level armor it is.
It does matter if your supposed to be the tank and the monster is doing physical and magical damage of a type(light,ice,etc) in Dekaron. A quick list for you: DF resistances Fire,Curse,Poison. Abyss resistances. All(depends on spawn order given). Crevice A,B,C - Fire, Light, Poision, Curse.
120+ tips: 75% resistance method at higher levels(Dekaron Dil): 1 necklace, 1 helmet or armor with 4*9% resist gems, strengthened dark eye, +4 or above pants. The above metioned method allows you to max 2 resistance at one time.
You can do 3 resistances almost fully maxed(75%=max) by wearing helmet 4*9% resist 1st type, armor 4*9% resist 2nd type, necklaces*3 of 3rd type, strengthened dark eye, +4 or higher pants, Level 5 Resistance buff skill(Maxed) good for inside the gate room in deadfront.
Max your AOEs. Max masteries. Learn your skills, you won't need Dekaron Dil to use temperance to the limit(stupid knock-back suppression), if your tanked up correctly with the right gears equipped for the situation you are in, you will be able to outlast your party and if you have temperance to the limit on you will notice you take much more damage than you would without it.