Another thing that I think takes a little getting used to coming from 3rd (or Pathfinder) to 5th is the idea of bounded accuracy: https://olddungeonmaster.com/

Another thing that I think takes a little getting used to coming from 3rd (or Pathfinder) to 5th is the idea of bounded accuracy: https://olddungeonmaster.com/2014/08/30/bounded-accuracy/ https://olddungeonmaster.com/2014/08/30/bounded-accuracy/ The TL;DR is that AC/attack bonuses/saving throws/save DCs used to scale a lot more than they do now. The upshot of this change as a DM is that you can plan out encounters differently. Feel like your first-level characters aren't getting enough of a workout? Throw a CR 3 or 4 encounter at them. I ran Curse of Strahd as my very first 5th Edition campaign, and there was an encounter at the end of the early section where I'm like, they already lost one character earlier in the dungeon, this is a straight-up TPK. But they handled it fine, although they used about a day's worth of abilities/spells that recharge with a long rest in a single encounter. That's where I started to get a much better feel for how encounter balance works in 5e.