There are four types of damage in Eve (kinetic, explosive, thermal, EM), and the last time I extensively played the game, most NPCs only used one or two types of damage (with only a few tough ones using all four). So you generally only needed to boost your ship's resistance to a couple of types for a given mission.
However, it's been a while since I played, and there have been a lot of changes to the game. So I'm wondering how the NPCs have changed - are they still mostly using two damage types (and the same each time), so it's worth looking it up and planning for? Or do they use all types, and/or change what type they use, so you have to be prepared for anything?