Question: I will be playing my first 5e session here soon. I got to skim the basic rules PDF, so I know that it plays a bit like 3.5 with some modernization. (*Please don't stone me if I'm oversimplifying that*.) I'd like to know what I should bring in my dicebag.

*I know that it's usually best to have one of each dice in D&D, regardless.*

That's not the point. The point is that I'd like to know if gameplay can be improved/hastened by having multiples of any of the dice.

For example, casting *fireball* in 3.5e without a big stack of d6's was a *very slow task*.

Likewise, there were many, many instances in 4e where multiple dice of the same kind were rolled. Especially so for damage rolls on Encounter/Daily powers: [2w], [3w], etc.

**Would be wise to bring extra dice of certain types?** I'm open for **theory** based on your understanding of the rules and what **may** come up as much as I'm interested in **personal experience**.

Answer: 
Yes
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You should bring extra dice to *any* roleplaying event. In large numbers.

There are many situations where you need more dice and they are for the most part independent of the actual system you are playing:

* Maybe 5 enemies attack. All with the same stats. Roll 5 dice.
* Maybe all 5 hit and the character needs to dodge 5 times. Roll 5 dice.
* Maybe someone forgot their dice. Just give them half of yours.
* Maybe you got a bonus and your grenade or fireball does double damage. Roll all the dice together.

And finally, if the enemy evil boss monster has just one life left, the barbarian is taking a swing with it's double-bladed laser axe of instant doom aaaand... *you roll your single die a bit too enthusiastically... off the table, over the floor and under the cupboard*. That's it. The die is gone. End of epic scene. **Or** you just ignore that one die, take the next and kill the big bad evil guy.

Dice are dirt cheap. You need to make sure you buy *dice* and not *brand names*. If you do, a hundred will cost you less than a meal at your favorite burger place.

Bringing only a set amount of dice because "I don't need more" is like bringing a set amount of candy because "I will not want more". Yeah. Like that ever worked :)
In my experience (I have a 5th level Ranger/Rogue in my current group), and if getting more dice isn't a hassle, I would for sure bring **2 D20(for when you need advantage or disadvantage), 1D12, 1D10, 1D8, 1D6, 1D4** for each player. 

*Additionally* I would look at each player to see what their most common attack is. For my ranger I use a short bow, with Hunter's mark, and Colossus damage often. (2D6 and 1D8) So as far as additional dice it all depends on what characters and their attack rolls they use the most. From the sessions we have played together we have 10D6 for a fireball and then borrow others dice when we score a critical and roll double or just roll it twice. 

In conclusion if I was a new GM I would again bring **2 D20,1D12,1D8,1D6,1D4, per player and have 1D12, 1D10, 2d8, 10D6, 2D4** on the side so they are quick to grab and use for when players score critical hits or when their attacks involve multiple dice. These are the dice I have used most often in my games. You could always have even more dice on the side if you are worried but that is where I would start.