Spell components and costs

[Intregus182]

The edition of D&D shouldn't matter too much here but these are my questions:

1. When homebrewing a new spell how do you determine what spell components(M, S, V) are needed?

2. How do you determine when a material component needs to be a costly one like a diamond?

3. How do you determine when a costly component like a diamond is consumed as part of casting the spell?

I'm very curious to see what different methodology people use.

Edit: Also when do you add concentration to a spell vs allowing a spell to be active without concentration?

[KittenMagician]

The edition of D&D shouldn't matter too much here but these are my questions:

1. When homebrewing a new spell how do you determine what spell components(M, S, V) are needed?

2. How do you determine when a material component needs to be a costly one like a diamond?

3. How do you determine when a costly component like a diamond is consumed as part of casting the spell?

I'm very curious to see what different methodology people use.

components: M is not too terribly important as far as being a limiting factor, S is normal for most spells, and V is normal for most spells. If you think the spell should be castable while tied up (S) or (S,M) if not castable while tied up add in (S). castable while silenced no (V)

costly materials: if you think the general populace should not in general cast a spell, add a component worth 10+gold. (identify, find familiar, chromatic orb are a few examples).

Consumption of materials: this should be for spells that do something quite strong like revivify or any other resurrection spell. the more it does or the stronger the effect, the more likely it is to consume the components

[GalacticAxekick]

1. When homebrewing a new spell how do you determine what spell components(M, S, V) are needed?

My thinking is pretty simple. If the spell involves a physical action such touching a creature or manipulating an object, it gets a somatic component. If the spell involves speaking to another creature, it gets a verbal component.

If a spell involves neither speaking to a creature nor manipulating an object, it should probably still have at least one component. This creates a clear relationship of cause (spell component) and effect (spell effect) that creatures can use to identify the spellcaster, or to interrupt the spellcasting, which is important for balance.

For example, a spellcaster shouldn't be able to cast Fireball while gagged and restrained. Fireball's verbal and somatic components are thematically arbitrary (why do you need to point and yell to make the explosion?) but mechanically important.

To decide what arbitrary component I'll give a spell, I think about what limits I think a spell should have. For example, I think most combat spells should fail when the caster is restrained. Somatic components are perfect for that! But I also think that teleportation spells should work perfectly when the caster is restrained. Verbal components are perfect for that!

The only spells that I believe should have no components at all are divination spells. With a few exceptions, I think casting a divination spell should be as simple as thinking, looking or listening.

2. How do you determine when a material component needs to be a costly one like a diamond?

If the material component isn't consumed by the spell, I ignore it completely. Costly or otherwise.

The only exception is with slow-to-cast spells that imply some form of ritual. For example, Scrying takes 10 minutes to cast and involves a 1000 gp crystal ball. Obviously the spell is cast by gazing into the crystal ball, and if a character wants to interrupt the 10 minute casting process, what they need to do is take the caster's eyes off the ball. Having the option to do that is fun!

3. How do you determine when a costly component like a diamond is consumed as part of casting the spell?

Spell slots are recovered every day. But some spells should not be cast every single day (for example, resurrection spells). To prevent players (and NPCS for that matter) from spamming such a spell, the spell is made to consume a costly component.

[GalacticAxekick]

if you think the general populace should not in general cast a spell, add a component worth 10+gold. (identify, find familiar, chromatic orb are a few examples).

That's a very interesting rationale!

It relies on the assumption that the players are wealthier than average NPC of their level (which certainly wouldn't be true in any of my games), but in any game where that assumption rings true, that's a very elegant system!

[Intregus182]

Loving the responses so far!

I edited the OP to include concentration.

4. When do you add concentration to a spell vs allowing to be active without it?

[Tzardok]

For components it's also worthwhile to look at the class that is supposed to be able to cast it. Is it a bard spell? It needs a verbal component, no matter what. Is it a spell for assassins? Propably no verbal component; hard to stay sneaky if you are casting loud and clear. Is the spell for a divine spell caster? Adding a divine focus won't change much, but fit flavourfully.

Regarding the concentration thing: I would say that needing to concentrate should be for spells that you want to "occupy" the spellcaster. No other spells are supposed to be cast at the same time, for example because the spell is supposed to be awesome (like Earthquake). Concentration spells should also be spells that you want to give opponents a chance to interrupt even after successfully cast or those where it fits flavourfully, like a hit point drain over time.

[Vaern]

Most spells have verbal and somatic components. For these, don't ask whether the spell should have them. Rather, ask if there's a good reason for a spell should not have them. Glibness doesn't have a verbal component because it would kind of defeat the purpose of the spell if someone could hear you casting it. Dimension Door lacks a somatic component because it's meant to be a quick escape from being trapped, grappled, or otherwise immobilized. If you can think of a good reason to exclude one of these components, feel free to do so; otherwise, just include them as a default.

As for material components, I would consider the following:

Firstly, a good number of spells have non-costly material components that come across as a literal joke. A few lightning spells involve running fur over a glass rod, which can produce a static spark. Color spray requires a bit of POCKET SAND! Neutralize poison requires charcoal. Open/close requires having a key. If you can think of material components that will make someone think, "...maybe this isn't quite as magical as the 'wizard' wants me to believe," you should absolutely 100% put that material component on your spell.

Secondly, there's the question of general accessibility. Taking a character's spell components away can shut them out from using certain spells, even if the material component is not a costly one. Adding a non-costly material component to a spell may give the DM a bit more control if, for example, the players end up in prison or are similarly stripped of their spell component pouch.

Finally, there's a question of power. It's generally recommended that you compare a new spell's effect with existing spells to determine its relative strength. If your spell seems too strong compared to other spells of the same level but you can't justify putting it at a higher level for some reason or another, adding a costly material component can be a balancing factor to make the spell less accessible and prevent it from being overused.