Does the number of spells at a Wizard's disposal affect game balance?

Question

A Wizard learns two spells for free whenever they level up, and may learn additional spells by copying from spellbooks or scrolls.

For example, if there were two Wizards in the party, I assume they could each learn two different spells and then learn from each other's spellbooks.

Otherwise, the Wizard can either have only those two spells per level or, at the other extreme, all the spells, depending on what DM gives the player acccess to.

Will giving the Wizard a very large number of spells to learn from (for example, by having a high-level friendly mentor who charges no cost for access to their spellbook) cause them to become far more powerful than other PCs? I'm interested only in combat encounters.

Answer 1

A Wizard with hundreds of spells in their spell book cannot cast more than any other Wizard of the same level. Two Wizards of equal level prepare the same number of spells and can cast the same number of spell slots.

The Wizard with the large repertoire has more options and can fine-tune their selections if they know what they are going to face. Most adventurers don't have that much insight into what they are going to face so the advantage may be marginal.

On the other hand, a large repertoire can be a boon if they have the time, resources, and inclination to prepare scrolls ahead of adventures.

Answer 2

Yes. But it's not too bad.

Items, weapons, allies, spells, etc. picked up during adventuring can affect balance by making characters more powerful (or weaker if there aren't enough to go round).

The DM has to balance who gets what and when. In the case of wizards, the system helps by limiting how many a wizard can memorise each day.

More spells known can provide more tactical options, but only if the caster gets a chance to plan.

Consider for comparison that clerics "know" a vastly increased number of spells, but are limited by what their god gives them in the morning.

Answer 3

Game balance is Relative

There's no real way to determine if it is unbalanced per se. What it obviously gives you is versatility. Having a repertoire that can be custom fit to any situation is incredibly valuable. But balance is relative to several factors:

The Party

If your wizard is far more versatile than other party members, they may feel like the wizard is overpowered. A non-combat focused Warlock might feel like he is less powerful because you can do his thing AND combat things. Or a player might feel like you're killing everything and they aren't pulling their own weight because the DM has scaled up his encounters to fit you, which brings us to our next point.

The DM

Your DM ultimately has control over what is being thrown at the party. There's basically no way for you to be too powerful for him/her since they control the difficulty of encounters and other things. Being versatile has its benefits for both of you, since the DM can throw intrigue, combat, hunting, or anything your way and he doesn't have to worry about you not being able to handle it. On the flip side, he might want you to be outside of your comfort zone by throwing something you haven't planned for, and your versatility is defeating that purpose.

At any rate, you should check with your DM and your party if this is acceptable behavior for your wizard. They all need to be prepared for you to have a huge arsenal of spells and plan accordingly.

Mary Sue

"A Mary Sue is an idealized and seemingly perfect fictional character, a young or low-rank person who saves the day through unrealistic abilities" (Wiki). Your character is a story in the making. Having a character that can "do it all" might feel like poor character creation to some. The spells your wizard chooses can (sometimes: should) be influenced by your character's background, ideals, and flaws. "Jack of all trades, master of none" can certainly be a character flaw if you play it right, but you should be mindful of what this playstyle means for your character and more importantly, your party's characters and the DM's setting and story.

Answer 4

No.

It all comes down to opportunity cost. A Wizard with all the spells in PHB and other manuals still has only prepared Level + Int Modifier, a Wizard can have all the spells to choose from but he still has to choose and if he did not choose the correct utility spells going into a situation well he is out of luck.

Example: if he neglected to do some research on where he was going and didn't prepare Fire and Acid spells going into troll country well he will not be as effective as he could have been.

They have to weigh this spell against that spell and it pays to research where you are going and what the goal is to help with that. It is what a Wizard does after all... fights with his brain and the power that comes with it. Having all the spells simply means you have more options which is in and of itself a powerful thing but not overpowered.

Answer 5

The number of spells in your spellbook does little to affect balance

The main reason for this is that one of the major limitations as a wizard is how many different spells you can prepare in a day. After you prepare generally useful spells like Armor, Shield, Invisibility, Misty Step, Counterspell or Fireball, you typically have preciously few "free" preparation slots left for spells with more narrow applications.

It does not matter if you have a spellbook with dozens of other spells then. I speak from practical experience: I have copied many spells to my book that in the course of eight levels worth of play I have never even once used; and that even though I make it a point to prepare such subpar spells on purpose, to see if I can find some fun, creative application.

Maybe the most useful spells to add are rituals, which tend to see a lot of use as they do not consume spell slots if cast as a ritual. However, there are relatively few rituals to be had overall, and their effect tends to be utility, so they are certainly not unbalancing in combat.

Flexibility

The added flexibility from extra spells can be worthwhile, because you can balance your memorized spells to match the adventure you are playing, if you know what to expect. In a battle raid against a goblin tribe, memorize sleep, shatter, or freezing sphere. In an city detective adventure, memorize suggestion, detect thoughts and locate object. On a day securing your tower, memorize magic mouth, arcane lock and major illusion.

If you are only interested in the effect on combat encounters, then the benefits of this flexibility matter even less. If you already stuff all your memorization slots with combat spells, having even more combat spells in your book will matter relatively little.

Whats more, this added flexibility is fully accounted for in the description of the wizard class, which says:

On your Adventures, you might find other Spells that you can add to your Spellbook.

There is no limit imposed on this way of adding spells, neither in the PHB nor in guidance in the DMG. That is, the game accepts that you could add additional spells to the spellbook without limit, and without materially affecting game balance. Having a lot more spells in the book will not make a wizard "far more powerful than other PCs", it's part and parcel of the wizard class. (And from my experience, it also is very costly; my wizard is constantly broke, a further downside of adding extra spells).