If I were a paladin, I think I would be advertising my deity like NASCAR. When I think of the Templar knights of the crusades, those guys had crosses on their banners, on their helmets, on their tunics, on their shields, even on their weapons. I know there is no spellcasting benefit to having it on your weapon, but I would probably do it anyway just so my enemies knew who was striking them down.

I was thinking about having the arcane focus on my shield, but is there any reason you couldn't have several of them on you?

absolutely no reason you can;t at all, 
though my campaigns holy symbols have to be sanctified to work as a holy symbol, so you have to perform the ceremony spell ritual  on each one to make it usable same costs as making holy water recite prayers while sprinkling with powdered silver as the basic one, 

Same as my thinking. Hexblade why couldn't the pommel be your arcane focus?!

By that logic, why couldn't the pommel of any sword be an arcane focus?

But yet weapons are a no-go.

Makes perfect sense to me!!

Quote from AaronOfBarbaria >>

Somewhat recently, I've implemented a house-rule in my 5th edition games to make spell casting work the way it did in not-engaging-optional-rules AD&D 2nd edition and BECMI D&D, which works thusly: If you can speak intelligibly, and freely move your arms and hands, you can cast your spells (with the added benefit that casters of divine spells need only have their holy symbol in hand, rather than be able to freely move their arms and hands).

No material components needed, whether they cost a bunch or not and whether they are "used up" or not.

Because either the spells are balanced assuming that the players can actual cast them when they "need" to, or I'll see some huge unexpected problems arise by playing this way that will indicate that certain spells need to be moved to higher levels or entirely removed from the game.

House rule discussion - not part of RAW/RAI.

To borrow a page from some ancient edition of Shadowrun ( I think ), you could adopt a mechanic where the spell can always be cast, regardless of what you are able to do. It would theoretically be possible to cast a spell silently - merely by force of will - removing all spell components completely.

What you introduce is the possibility of spell failure. A spell cast using the listed components will succeed automatically ( within the limits of the spell's description ). A spell missing a component would require an Arcana roll to succeed. The DC would be selected based on the number of missing components. Verbal and Somatic omissions might have a straight penalty ( +5 to DC? ). Material component might have a penalty based on the rarity of the component ( +3 to DC per 100 gp value and/or level of rarity? ). Something like Resurrection should only be theoretically be possible to cast without the material component ( DC 30 ).

Additionally, you could introduce the concept of Rapid Casting  - compressing the casting time at an additional DC penalty ( perhaps +1 per 10% reduction of the spell's casting time, with 90% reduction being the max possible? ).

Examples.

Thordak wants to cast Fireball, while hidden in the scrub brush on the ridge overlooking the raider camp. If he stands up, speak the arcane words, makes the actions, and has the material components, then no issues ( DC 1, with no roll needed ) - but there's a good chance he'll be spotted. If he wants to try and stay hidden - no verbal or somatic component - and doesn't have the material components -  he can try casting it stealthily, requiring an Arcana roll with a DC of 16 ( Base DC of 1, +5 per missing component ).

The adventuring company Whitegarde is fleeing down the narrow canyon pass, attempting to escape the pack of slathering Ghouls trying to run them down. Wealda spins around and slams the butt of her staff into the ground, reaching into her belt pouch to pull out a pinch of phosphorus. No time to to do this right, the Ghouls are almost upon them! Concentrating hard on the words and motions, she needs to pull the Fire Elemental through now! Trying to cast a 1 minute spell in 1 round is a 90% reduction. She needs to make an Arcana check at a DC of 10 to pull the spell off.

Totally house ruling it here. But it allows the utility and flavoring of components, without making some spells unusable because the character lacks the components; they're just a lot harder to do.

Quote from TexasDevin >>

By that logic, why couldn't the pommel of any sword be an arcane focus?

But yet weapons are a no-go.

 there you get to the heart of what is an arcane focus,

is it a special object that allows you to form a greater connection with magic as in the wands in harry potter, get the wrong one and suddenly you've lost your eyebrows.
or is it any old lump of crud

if it's the former then you need the right sort of crystal formed in the right way and added to the weapon in the correct manner for it to work.  (i.e. my way as i'm all for anything that makes the players lives more complicated and gives me opportunities for little side quests and downtime research topics)

or the latter, just use any old crud it doesn't matter
which route you chose depends on both you and your players.

For me, the reason that not just anything can be a focus is a question of equipment setup balance. You must choose between filling your hands with weapons and shields, or keeping one hand free to cast all spells. To that end I consider a hand holding a normal focus (a wand or mistletoe sprig or whatever) to be absolutely the equivalent of an empty hand that has access to a component pouch. That is, able to cast S spells and M spells, and able to consume gold cost materials. The only exception is for a focus that is also a weapon or shield (staff/quarterstaff, ruby enhanced weapons, pact weapon or holy shield); these focuses can be used to cast M spells but not S spells (without M). War Caster allows S with those focuses as well. I let any character use any reasonable object as a focus, as long as they obey the weapon/shield restriction and they aren't trying to take the piss. Many magic objects could also be used as a focus as long as they are carried in a hand and aren't a weapon. Focuses must be visibly magical, they are never easier to hide than a component pouch. No mechanical advantages!

The point of arcane focus/component pouch/basic material components I'm just calling this [stuff] from now on) is to balance spellcasting with the use of weapons. A fighter without his sword is less capable and more restricted but isn't useless - he can still fight but not as well. The spellcaster losing their [stuff] is less effective as they are restricted to the spells not requiring these. Material components at a cost are to bring some balance to spells that are more powerful than others of their level.

If you are looking to completely remove this requirement then you are giving spellcasters a greater advantage over other classes who rely on weapons. The only exception is the monk but their balance comes from how basically everything they do requires ki which is a limited resource. And I say this as somebody who hates the whole mechanic of [stuff].

In all games I play there has been a house rule where if the material component is not consumed then you don't need to actively handle the [stuff] unless you want to but you still need a hand free for somatic casting and to be able to speak the words for verbal components. The [stuff] just needs to be on your person like in a pocket or something. This homerule is also used on Critical Role - although Liam and sometimes Sam, does make the use of material components as an RP choice but that is his and Sam's personal choice. Matt doesn't force them to and there have been characters who cast their spells without needing to actively handle [stuff]. There have even been occasions where enemies have casted material-requiring spells without any handling of [stuff] only for the group to find an arcane focus tucked in their pockets. The NPC Gilmore used a ring.

This houserule keeps the balance (the [stuff] can be removed from their person) but otherwise doesn't have the character juggling items in combat. I find this image rather silly in my head even when it's used well (like in Dresden Files - totally recommend this as it follows a Wizard with decent portrayal of magic including "material components", but don't watch in "as aired" order because it was aired in totally the wrong order and will be confusing (and lead to the cancellation of it after 1st season which is a crying shame) so look up the right order online and give it a try). I find it especially weird for Sorcerers whose power is something they are born with and should not be reliant on items they find - an idea shared by Paizo when they made 2e Pathfinder as their Sorcerers get to ignore material components but there's no "cost" system to material components and their rules are ALOT more complicated.

Anyway, much as I utterly loathe the material component system (something I miss from 4e was how no spells had these only rituals did) it will be difficult to do away with it completely without causng a potential balance issue. If you make changes to this have a serious talk with players about the implications it may have and ensure everyone is OK with it).

Does the arcane focus need to be held in hand and presented as part of the casting of the spell? Or can you just have it on your person? 

Quote from HeyDare >>

Does the arcane focus need to be held in hand and presented as part of the casting of the spell? Or can you just have it on your person? 

Held in hand and presented as part of casting the spell. By RAW anyway, every game I have played has allowed homebrew rule it just needs to be on person: even Matt in Critical Role uses this homebrew rule.

Quote from TexasDevin >>

By that logic, why couldn't the pommel of any sword be an arcane focus?

But yet weapons are a no-go.

It is to require meaningful choice.

Want to hit someone with a weapon? You need a hand to hold the weapon. Want to protect yourself? You need a hand to wear a shield. Want to cast a spell? You need a hand to hold a focus and make magical gestures.

Want to do all three? You can't (unless you are a thri-keen). You have to make a choice.

Choices are good - they are pretty much at the heart of good games.

Quote from HeyDare >>

Does the arcane focus need to be held in hand and presented as part of the casting of the spell? Or can you just have it on your person? 

Held in hand, or touched with an empty hand as part of the casting. You could use a crystal amulet as a focus, but to cast an M component spell needs an empty hand to touch the amulet and draw out its power. A priest could use their holy vestments, but again, empty hand.

The purpose of the focus/component pouch for Material components or the empty hand for Somatic is to force the choice between holding weapons and shields vs keeping hands free for casting via the components.

A character can use a component pouch or a spellcasting focus (found in “Equipment”) in place of the components specified for a spell. 

Not meaning to necro-bump, but I'm hosting a campaign soon so I wanted to get clarification on some of the finer notes.

The context says "x or y in place of the components specified for a spell." I think the key word there is "a," as in a single spell. Which explains why a wand of fireballs or glove of blasting might exist as a magic item, as a focus for these specific spells(that is magical because it removes spell slot cost and usually has multiple uses in one day).

At least that's how I'll interpret it. I might compromise with a player who really wants to avoid using components later in the game and say that their arcane focus will be upgraded as the campaign moves along, but for most ritual spells and cost consumption spells they'll have to stick with components. I also just find joy in seeing how people use their components to make their spells sound interesting, instead of just "I wave my wand and cast blah blah blah." yawn I want to see some RP in my RPG

RAW and RAI simply means "a spell" as the category of "spells", not "a single use" of one spell casting. And like the components of a spell, are not consumed.

However, a focus can't be used to substitute for components that have a gold cost (such as a diamond in Resurrection spells) or components that are consumed (such as the items in a Create Homunculus spell). In which case the exact items must be used.

That being said, as DM you get to make the rules!

Quote from AmazingAmazon >>

I'm aware of rules guys I was asking how people handle it in gameplay sorry if that was not better implied!!

I play it the way it reads in the rules. The component pouch has any component the caster needs unless the material component has a cost associated with it. In that case the caster must purchase and track those components to use the specific spells. An arcane focus works exactly the same way, and is just a flavour difference. Both require a free hand.

Edit: Just realized this is a zombie thread. Die, Zombie, Die!

Quote from HarbingerX >>

Quote from AmazingAmazon >>

I'm aware of rules guys I was asking how people handle it in gameplay sorry if that was not better implied!!

 

I play it the way it reads in the rules. The component pouch has any component the caster needs unless the material component has a cost associated with it. In that case the caster must purchase and track those components to use the specific spells. An arcane focus works exactly the same way, and is just a flavour difference. Both require a free hand.

Edit: Just realized this is a zombie thread. Die, Zombie, Die!

In AL I play a Drow Cleric of the Trickster, it's a stupid flavor but the table absolutely loves it, any time I cast Guidance on someone I slap a sticky note that says "kick me" or something prankish on their back. I have to roll for sleight of hand but everyone finds it to be a great addition to my character.

And then I dipped my pinky into Rogue, and I found a pair of Gloves of Thievery. So I'll probably never get caught at this rate ahaha

my dm gives one mechanical advantage to pouches.  he lets us carry enough of costless components that are consumed that we never have to worry about it till after we have had some downtime where it is assumed we restock so we can use pells that consume worthless things with a pouch but not a focus

Quote from duelistjp >>

my dm gives one mechanical advantage to pouches.  he lets us carry enough of costless components that are consumed that we never have to worry about it till after we have had some downtime where it is assumed we restock so we can use pells that consume worthless things with a pouch but not a focus

 
So in other words he treats component pouches like... regular component pouches?

Most of my arcane foci are kind of like Harry Potter wands. They have all the necessary stuff inside the core of the (wand or whatever).