Pros and Cons of multiclass warlock/wizard

[Yora]

I am completely new to the game and just reading through the PHB.

And I was wondering how much it would be worth for a warlock to multiclass into wizard to get some additional low-level spell slots. You get access to higher level spells late and fewer incantations, but more spell slots seem always nice to have.

[Particle_Man]

Usually people mix warlock with sorcerer instead of wizard so that you can dump int and focus on chr, con and dex. Also starting with sorcerer gets you good con saves and you can have fun with turning unused warlock spells into spell points every short rest, which in turn can become metamagic or more sorcerer spells.

[sophontteks]

There is very little to gain and I wouldn't recommend it. I wouldn't recommend multiclassing at all until you've played a few. 5e classes are solid on their own. If you multiclass without a clear plan and knowledge of the consequences, you risk making a very unfun character that struggles to keep up. It could ruin your entire experience.

[McSkrag]

There are couple things to keep in mind in the current system is that all of the classes have been designed to be played as a single class from levels 1-20. As long as you maximize your primary ability you can't go wrong.

To answer your question, wizards cast with intelligence and warlocks cast with charisma so there is not great synergy there.

For more in depth info there are a bunch of useful class build guiders here along with a multiclassing guide:
http://www.giantitp.com/forums/showthread.php?377491-Guides-Tables-and-other-useful-tools-for-5E-D-amp-D

[MaxWilson]

I am completely new to the game and just reading through the PHB.

And I was wondering how much it would be worth for a warlock to multiclass into wizard to get some additional low-level spell slots. You get access to higher level spells late and fewer incantations, but more spell slots seem always nice to have.

I've done it before (Cthulhu Warlock 2/Necromancer X with high rolled stats). You need a plan for how to use the extra spell slots/invocations but overall it's fine. Now that Hexblade is out, a tanky Hexblade 2/Necromancer X would probably be fairly fantastic, with plenty of first-level slots for Shield and Wrathful Smite to complement all the arrows from your skeletons.

Abjuror/Warlock is also fairly famous (due to the Armor of Shadows/Arcane Ward synergy that lets you heal your Arcane Ward between combats for free, plus the Armor of Agathys/Arcane Ward synergy that makes Armor of Agathys last longer and therefore do more damage). I'm not all that impressed by it myself but if you did want to make a melee-oriented warlock/wizard, Hexblade/Abjuror would probably be the way to go.

[Ganders]

Multiclassing for spell slots is common. My warlocks almost always want to do it at some point -- but not for the spell slots alone. Remember it's always a tradeoff. Every time you gain one-levels-worth of features from another class, you miss out on one-levels-worth of features from your class. There is an endless debate: some people say multiclassing is clearly worth it, maybe even overpowered, other people say it's clearly worse and never worth it (in addition to being more complicated).

True, many warlocks feel the crunch of having only two (or later on 3-4) spell slots per short rest. (1)

But there's another factor: At higher levels you really miss having low-level spell slots because some of the low level spells don't scale up. Spells like Comprehend Languages, Darkness, Mirror Image, Mysty Step, and so on are no more effective in a fifth level slot than a first level slot. It seems like such a waste to use a fifth level slot on them, so adding a few low-level slots from another class is nice.

There's also a third factor: limited spells known. (Sorcerers face this same issue).

Consider a tenth level cleric: At any given moment, if he wants to cast a spell, he must choose which of his 25 known spells to cast. Now consider a tenth level warlock: At any given moment, if he wants to cast a spell, he must choose which of his 10 known spells to cast. Knowing only 10 spells instead of 25 is, it turns out, quite constraining. But it gets worse: clerics and wizards can swap out what spells they prepare each day. In the course of a week-long adventure the cleric or wizard might cast 80 different spells. Not that he'd necessarily want to -- most casters have a few favorites that they use every day -- but the point is he could. In that same week, the warlock is still limited to those same 10 spells. 10 instead of 80 is an even bigger gap than 10 instead of 25.

Multiclassing into ANY other caster will add more spell slots. Bard and Sorcerer are the most popular because not everyone has high enough Wis or Int to multiclass into Cleric or Wizard. But if you do manage to take wizard, cleric, or druid, you also get the ability to swap out prepared spells every day, which is quite helpful.

(1) One of the more popular solutions for spell slots is to simply have more short rests during each day, perhaps by making short rests take less than an hour. Another popular solution is to extend Mystic Arcanums to all levels, not level 6-9 spells only. But really, you need to get a good feel for how things actually work in actual play before you fiddle with things too much. Try to remember that warlocks have so many cantrips, invocations, and special abilities that they could almost be a viable class without any spells at all.

[Laserlight]

As I understand it, the devs originally intended to have warlocks use INT for casting. That makes sense to me and I would allow it at my table; if your DM agrees, that would make warlock/wizard a lot more palatable.

And yeah, I'd seriously consider MCing with something to get more slots. Having fourth or fifth level spell slots is nice but you hate to cast Shield or Darkness with that.

[Yora]

If opinions differ so much, it's probably pretty good design. There's no clearly superior choice, just personal preferences.

[CTurbo]

A couple levels of Warlock can be extremely good for an Abjuration Wizard.

Warlock 2 gets you 2 cantrips, 3 spells known, and 2 spell slots that recharge on short rests, light armor, invocations and of course a Patron. All Patrons offer something useful, but Hex would really up your AC a lot with medium armor and shield proficiency.

The key here is Warlock opens up a couple more good Abjuration spells that you wouldn't otherwise have access to like the excellent Armor of Agathys.

Armor of Shadows lets you replenish your Arcane Ward at will.

[Kane0]

If you have the cha and int for it by all means. Most people tend to avoid the MAD by choosing paladin, sorcerer or bard instead of wizard to pair up with warlock because they all use charisma.
But yeah, you trade higher level spells and class features for more slots, invocations and other minor goodies. Its not bad.