How to allow cantrips to be changed

Question

The wizard in my game has requested the ability to change out his cantrips similarly to his higher level spells. His justification is that every other wizard spell is memorizable, so having fixed spells seems antithetical. I kind of agree with him.

I know that there is no mechanism for changing cantrips, but I'm trying to come up with a fair means of doing so.

The two extremes, as I see it, are:

1. Cantrips can be swapped out just like preparing any other spell.
2. Retrain a the cantrip, taking 250 days of Downtime, as if learning a new skill.

I'm interested in having a good middle ground option, patterned on other rules, if possible.

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Here's the house rules I have tentatively decided on. Critiques welcomed.

Cantrip House Rules

For all following rules, when using a cantrip that you don't currently "know", for classes that use a spell book, the cantrip must be in the spell book. Cantrips count as 1st level spells for purposes of price and scribing.

• When you gain a level, you may swap one cantrip for another that you have available.

• As a Downtime Activity, a cantrip can be swapped for another that you have available after 10 days of practice and the expenditure of 20gp.

• Cantrips can be prepared and cast as 1st level spells. If the cantrip effects improve with level, the spell slot used to cast it must be 2 levels higher per step of improvement.

• Cantrips can be cast as rituals. The cantrip improves with level as normal.

As with any house rule, I reserve the right to change it if it breaks.

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Be warned! My DMing style is quite liberal. If you use this, wizards, druids, & clerics in your group may become unbalanced.

Answer 1

The idea with cantrips is that those are spells that the wizard is most familiar with. He used/practiced them so many times that he can use them at will, effortlessly. It doesn't make much sense that he could forget one of those and perfect another in a short span of time. For a permanent effect, I would agree that he could change it during Downtime.

If your player really regrets one of his choices, though, and you're not planning to give them downtime any time soon, you can think of a special one-time mechanic just to accommodate this change. For example, he could get possessed by a ghost of an ancient wizard during an encounter and his mind could get permanently altered as a side effect. You can always add other fun side effects as a "price" for such catering to the player's wishes, like strange visions or making his magic more unstable (always hurting him on a critical miss).

If your player just want the ability to occasionally use one of the cantrips he does not have, let him. Just make him use a spell slot for it. Any cantrip can be reasonably used as a first level spell in its weakest form. If he wants to use a stronger version of the cantrip, make him use more slots. You can look into how much damage it would do compared to regular spells to decide on the appropriate number of slots. If it's not a damage cantrip, one slot per improvement should do it.

Personal example of cantrip roleplay:

When I made my cleric, I thought carefully which cantrips would make sense for my background, so I chose Mending as one of my cantrips instead of something that would usually prove more useful (like Light). I've also avoided taking Guidance at first level, as I plan to build up to it through our campaign by continually assisting and advising my fellow adventurers. If a change of a cantrip would ever be more than a change in mechanics of the PC and actually make sense and contribute to the roleplay, then I would petition for it strongly. Otherwise, I'd say it's dabbling dangerously in the realm of min-maxing.

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While I agree that being able to change one cantrip per level is mechanically sound, I'm still unsure if it fits from a roleplaying perspective. Maybe one every two or three levels. But I am leading only a low level group, where the time between levels is relatively short. If your players are around level 10, it might be enough time to retrain a cantrip. Especially if they're traveling in between distant locations, with not much happening on the road. The player should definitely roleplay the activity, though, making sure to note he's training the cantrip of his choosing.

On that note, some sort of training regime could be an additional mechanic. You could specify the number of training points required to change a cantrip. The player could then roll the die of your choice every time he trains (at maximum once per long rest) to accumulate training points. Or, he could spend a spell slot to do it, enabling him to spend all of his unused spell slots before his long rest. That would speed up the training the more unused slots he has, but leave him open to the risk of being "too tired to cast proper spells" in case of a surprise ambush during the long rest.

The "using unspent spell slots" scenario fits roleplaying well, too. For instance, if a player would want to learn Ray of Frost (1d8 damage), he could say that instead of casting one 1d8-damage ray he's casting 1d8 one-damage rays. After a sufficient number of rays cast, you'll say that the player has perfected the spell and can use it at will from now on. This would, of course, only be possible with cantrips, as the other spells are "too complicated" or "require too much energy" to be cast without spending a slot.

Answer 2

Tasha's Cauldron of Everything has added (optional) rules for switching out cantrips

Tasha's Cauldron of Everything (p. 76) adds an an optional class feature for wizards at 3rd level, called Cantrip Formulas, that allows them to switch out cantrips:

You have scribed a set of arcane formulas in your spellbook that you can use to formulate a cantrip in your mind. Whenever you finish a long rest and consult these formulas in your spellbook, you can replace one wizard cantrip you know with another cantrip from the wizard spell list.

This is an optional class feature, however, and needs DM approval before it may be used.

Answer 3

Allowing a wizard to have all the wizard cantrips at his disposal and being able to swap them around on a long rest like his other spells will give him a huge advantage. Many of the wizard cantrips offer different damage types, being able to swap to one that targets a creatures vulnerability whenever he comes across something different is huge.

Wizards are already flexible as it is and cantrips for all classes are quite powerful in their own right which makes picking the ones you feel are important to your character right.

If he feels he has made a mistake with one and would rather have another, I believe the fairest option would be allowing him the ability to swap 1 single cantrip for another when he levels, much like other classes can swap out one spell for another when they level up.

Answer 4

When he levels up, let him choose to unlearn one cantrip in exchange for another. Similar to how the RAW allows Sorcerers and Bards to trade out non-cantrip spells when they level up.

Answer 5

If you allow feats in the game, remind your player that they exist, and can be taken instead of one of their class's stat increase.

There are several feats in 5e that give small boosts to a character's casting ability. Note that only Spell Sniper requires you to be able to cast spells already before taking it.

• Magic Initiate: 2 cantrips from a chosen spell list, as well as a 1st level spell that is usable 1/long rest.

• Ritual caster: start a spellbook, and learn 2 spells with the "Ritual" tag from a chosen class. You can learn more Ritual spells later as you encounter them.

• Spell Sniper: All your spells that make an attack roll have double range and ignore most cover, plus you learn an attack cantrip from a chosen spell list.

While none of these allow a player to swap out their character's known cantrips, they do allow some to be added, possibly replacing the need for it.

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I'm adding this answer for completeness. It's a different method that might be preferred by DM's who have dislike houserules and homebrew. Additionally it allows greater flexibility in a way, because even if you are already a caster of some variety, you are not required to choose that spell list with these feats, giving access to one or two choice spells from a list you could not otherwise access.

Looking over the house-rules you adopted, they seem quite reasonable. An updated on how they have worked out in practice would be interesting.

Answer 6

This is an irritating one. As a player, I want to say yes, let him switch them out. As a DM, I want to say no, don't make it easy. Based on the description of a cantrip for a wizard, it is a magical skill rather than an actual spell. That said, I would really want to decide it on a case-by-case basis. Are we talking firebolt or prestidigitation? At any rate, rather than letting him change it, I have a very simple solution that is not exactly a houserule and rather elegantly circumvents the problem.

Step 1. Let him add cantrips to his spellbook, but not cast them. (Is this a houserule? I think a wizard could do it simply because a wizard cantrip is still a wizard spell.)

Step 2. Let him craft spell scrolls for those cantrips, using the optional (at least, I think they were optional) rules that are either in the PHB or DMG (I forget which.) If you are feeling really, really kind, let him craft wands for cantrips. (Super houserule-y option, but slightly more balanced than actually switching cantrips.)

Answer 7

People tend to forget things they don't do/use often, like a language or the use of a particular tool/program.

If a player regrets taking a particular cantrip, they probably don't use it much either. I would totally allow a player to swap a cantrip when leveling up if they haven't used it much in the last games since that'd make sense in the game.

I would also encourage the player to justify the new cantrip during the campaign prior to leveling up. For example, if the player wants to swap an unused cantrip for "shocking grasp", they should try to use more lighting-elemental spells than usual. Also, the DM could include more enemies that use the element, so the player has a way to train and learn the cantrip.

You could also force the characters to train the new cantrip during downtime. Be it with an NPC that knows the cantrip (and paying them accordingly) or by research (using a fraction of the resources but taking longer time). I personally don't like to make the players train stuff they'll learn when leveling up, since the experience they earn during the game should be what teaches them the perks and skills they'll get at the new level.

Answer 8

Elegant houserule;

1. Wizards can change out cantrip selection on a 1:1 basis each time they level.
2. By eschewing the use of two cantrips when preparing spells, a wizard may use 1 cantrip he does not know for that day only. A wizard may do this more than once while preparing spells.

Introduce a feat or other option to learn additional cantrips on a permanent basis if he wants to make that flexibility a permanent part of the character.

Answer 9

Fair and Play-Balanced Retraining

Retraining is a big perk. If a wizard can re-train beyond what is allowed in the rules, all classes should be able to.

I have allowed retraining a class build option at leveling-up, similar to the rules in fourth edition:

When leveling up, a character may change one class build node option for a different choice. This can't involve eliminating anything physical in the game world.

Node Option?

By node option, I mean a decision you make when building your character that neither involves making additional choices, nor grants multiple powers as different levels.

Choosing a different Battle Master combat maneuver is a "node", but switching from Battle Master to Champion is not. Schools of magic, divine domains, sorcerous origins, etc., are also disallowed for retraining under this rule.

Examples

• A cantrip known because of class can be changed, but not one known because of race.
• A skill learned because of their class can be changed, but not one known because of their background. (Although if a skill might have been learned from either the background or class, I'll give the benefit of the doubt.)

Physical Manifestation Exception

If a class option involved creating something physical in the game world, such as a wizard adding a spell to their spellbook, that cannot be retrained. (This does not apply to cantrips, as they are always memorized.)

Limiting Minmaxing

These rules are pretty generous, and are easy to abuse by minmaxers. (I've used them for running games for new players and kids - I generally wouldn't be so generous with experienced gamers.) Damage cantrips, for example, are more useful at levels when they increase in damage (e.g., 5th level) than at other levels.

If you find some players leveraging this rule to really minmax instead of just figuring out your characters, you might want to limit it to one every two or three level-ups.

Answer 10

Was thinking about this problem myself... after reading several excellent suggestions, here's what I'm considering:

After you recover spell slots at the end of a long rest, you spend one 1st-level spell slot due to the magical energies consumed practicing your new skill. After doing so for 3 consecutive long rests, the magic has become second nature to you and can be cast at-will. To enable this dedication, you choose an existing known cantrip, which cannot be cast without consuming a spell slot during the entire training period and is no longer known at the conclusion.

I think this solution fits well from a roleplay perspective as it has logical mechanical consequences of time spent neglecting one spell-skill while training another. It also solves the somewhat counter-intuitive problem of linking to level-up; since doing so effectively means that novice characters have an easier time mastering new cantrips than high-level casters.

**I realize there is now an official mechanism for what was originally asked, but it's optional and only covers Wizards. The question and nearly all the answers on this question contemplate homebrew and could work for nearly any caster, so I added another answer that is homebrew and works for any caster class.

Answer 11

Try to find out why your player wants this versatility from cantrips. These spells are mainly as a last resort if he runs out of regular spell slots or to create minor magic effects without expending slots. If he is one of those creative magic use to the fullest types then simply give him the opportunity to learn more utility spells of the regular levels. Or maybe give him more one shot items. Of course only if it does not break your campaign. Spells carefully to be considered are e.g. Fly levitate teleport etc. These work well in one campaign and can cause major dm headache in another. That's the reason why I for instance always reserve the right to disallow specific player selected spells in the campaigns that do dm.