D&D 5E The number after "Hit: X" in the bestiary?

[TerraDave]

Its faster.

Minions had fixed damage in 4E and worked just as described above, and it worked pretty well.

For the red dragons bite, I would also still probably roll.

 

[Jeff Carlsen]

Average damage is a handy tool when I have a bunch of monsters. I don't like sitting there rolling a lot while my players wait, I want to get back to their turns. But with a small handful of monsters I prefer to roll.

 

[Sadras]

I'd xp you, but apparently I need to spread it around some first.

Covered, I was already Xping him, before I read your post. What he does is just too awesome not to!

 

[Prickly]

I use the average damage a lot when I dm.

It makes my turns very quick even with a lot of monsters on the board and I can run a game with a single d20.

 

[Plaguescarred]

I always perfered to roll damage but i must confess the static average damage has proven to be handy on more than one occassion when an encounter had multiple monsters.

 

[TillForPie]

As others have mentioned it's helpful if you're dealing with a lot of monsters. Further, it provides at a glance the amount of damage the creature will be doing per hit on average and a good picture of what it'll be doing to the PCs. Considering it takes up hardly any space its presence can really only be a good thing.

 

[darjr]

I'll sometimes roll, but usually only when there is some effect triggered by the amount of damage