Why use Clairvoyance when Find Familiar is better in every way (except range)?

Question

I'm creating a spy wizard character in 5E. The character needs a 'wire' to tap a room of its visitors' information, and I was comparing two wizard spells, Clairvoyance and Find Familiar. Both have similar abilities in the sense that they allow sight and hearing into a remote location. However, for this use-case, Clairvoyance seems to be a terrible choice, considering the level requirement and reduction of abilities.

To help compare, let's use a table:

	Clairvoyance	Find Familiar
Level	3	1
Casting time	10m	60m (Inst. after)
Range	1 mi	100 ft
Duration	10m	Until Dispelled / 0hp
Senses	See or hear	See and hear
Truesight?	Glowing orb	Normal spider
Movement?	No	Yes

AFAIK, there are few cases where one would use clairvoyance. In what situations would a rational wizard choose to use a Clairvoyance spell in lieu of his familiar, given that a wizard can always be in range of the target.

Answer 1

Visibility, action economy and access

A familiar has to be physically present to observe a location for you. As such, it could be found and attacked if it is in hostile territory. The clairvoyance spell being present can only be sighted via certain spells or abilities.

To access the senses of your familiar you need to use your action for that turn and you lose access to your own senses. Clairvoyance doesn't have that limitation.

In order to scout with a familiar it needs to be able to access the area to be scouted. If it is behind locked doors then your options become a lot more limited. Of course, clairvoyance does require you to know the location being scouted.

Answer 2

Find Familiar can be useless or overpowered

It heavily depends on how the DM treats the creature. Is it a second player's character, a reliable magical device, or a living pet (extremely loyal, but still independent)? Many tables stick to the former option as easiest one, despite the rules suggesting the latter. Which is not a bad thing, but make sure you're on the same page with the DM before choosing the spell.

Here's a bunch of possible downsides of the Find Familiar spell comparing to the Clairvoyance:

The familiar might have trouble with getting to the spot

The Find Familiar spell says the creature "always obeys your commands". However, it always acts independently. The results may vary, since every creature is definitely limited by its own physical and mental capabilities. Even staying in the same place can be challenging (you can try this yourself).

So the Wizard just says to a rat "go to the Chancellor's Room and wait there" and hopes it understood the task and can handle it. Fortunately, a rat is not a spider — the latter has the lowest INT score possible and worse navigation skills.

Probably not a problem if the Wizard can physically visit the room beforehand and just leave her/his familiar there. But for how long? Let's find out.

The familiar needs supplies to sustain itself

The familiar is a living being, and nothing in the rules says it doesn't need food, water or sleep. See Do familiars cast from Find Familiar need to eat and sleep?

You can't just plant it in a room and leave it there for days. A bird cage with food it probably the best option for a (relatively) long-term surveillance. On the other hand, spiders can easily survive without food for days. However, here's another problem...

Familiar's senses might be limited

Spiders have eight eyes but poor eyesight, so they rely on touch and vibration instead. The same problem is true for bats, rats, lizards and most other forms except for birds and cats. The spell allow you to "see through your familiar's eyes", but it doesn't improve the creature's eyesight. The same is true for hearing — spiders are virtually deaf: they perceive sounds as touch. The DM might rationalize, that the spider isn't capable of conventional hearing, so when you "hear what it hears", you hear nothing.

And if a spider form was chosen as it's the smallest one, there's might be a problem with that.

A Tiny Spider is not so tiny

When you cast Find Familiar, the creature takes an animal form you choose from the list. However, you don't choose the particular size. You can't demand a extraordinary small cat. It is just a Tiny Cat. Or a Tiny Spider. Which can be the same size as the cat. This would be reasonable, since the familiar has to be big enough providing its capabilities of helping in combat or carrying up to 15lbs. See What, approximately, is the size of a Tiny creature?

The familiar is vulnerable

An obvious thing, but worth mentioning. Even if you managed to plant a little inconspicuous spider in the target room, and the DM ensures the spider gives you a perfect vision, the success is still not guaranteed. The spider can be eaten (by another spider) or smashed (deliberately or by accident). Comparing to this gambling, Clairvoyance is fail-proof and always leads to expected results.

Answer 3

Inaccessible and well guarded areas are where clairvoyance shines.

Find familiar is going to be useless if your familiar cannot get into the area you are trying to observe. A simple locked door makes clairvoyance “better in every way”, as you put it. Additionally, well guarded areas pose a risk of detection that clairvoyance can mitigate. The sensor is invisible, but the familiar needs make a stealth check.

Answer 4

In a word, location

A familiar is great, until you tell it to walk long distance. The spider has a movement rate of 20'. Meaning it can take dozens of rounds just to get where it is going. And every step of the way is a new stealth check. The event you're trying to observe may be over be the time they arrive.

Where as Clairvoyance can just appear where it needs to be, so long as you have either been there, or have a good idea of where it needs to be.

If you don't know where you're going, the spider will take forever trying to search, crawl through windows, under doors, backtrack, etc.

If you do know where, and can plant the familiar ahead of time, then it's a great option. Unless there is a great chance of being discovered while they wait.

Additionally, the area, or the path to the area, could be hazardous; other side of a ravine, behind a wall of fire, underwater, mid-air, etc. with 1-2 hp, the familiar won't last long if there is even a chance of getting hurt on the way, or while observing.

As for truesight, don't count on it. A familiar is, "a spirit that takes an animal form." And truesight, "perceive the original form of a shapechanger or a creature that is transformed by magic". So depending on the DM, they might rule that your spider looks like a glowing spirit.

Answer 5

What counter-measures does your target employ?

So, you want to spy on someone and are targeting a room they visit. You are relying on them speaking some secrets about something they do not want you to know, while believing that they have privacy.

And yet, as someone who has secrets, in a world where magic exists, they are likely taking counter-measures. How are they checking the room for bugs before they begin speaking freely?

Wand of Enemy Detection
Suppose your target and their associates are non-casters; fighter who are important personal guards, military commanders, prominent merchants or diplomats. If their conversation is particularly sensitive, and they have the means, a quick way to check privacy is by sweeping the room with a wand of enemy detection. This is a rare item, recharges at dawn, and while it requires attunement, it does not require attunement by a spell-caster. Anyone with secrets worth hiding would have one of these if they had the means. When they sweep the room, they are going to find your familiar: "you know the direction of the nearest creature hostile to you within 60 feet". Of course, they won't just be checking for familiars - there could be eavesdropping rogues and bards who have taken the Hide action, there could be wild shaped or polymorphed spies also pretending to be spiders. Remember that "hostile" means the creature 'opposes them and their goals', so any small animal detected by the wand is immediately suspicious and a reason to not speak freely. Your familiar will be rapidly detected and countered, but your clairvoyance sensor will not.

Detect Evil or Good
Now suppose your targets have access to first level spells. Knowing that someone might be spying on them, they are likely to employ detect evil or good. The spell, of course, does not detect evil or good at all - rather, it detects the presence of, among other things, celestials, fey, and fiends. Since your familiar is one of these, its presence will quickly be noted, with results similar to if it had been found via a wand, while a clairvoyance sensor cannot be detected this way.

Detect Magic
If your target has access to detect evil and good, however, they most likely also have access to Detect Magic, with the edge case exception of warlocks with a Genie patron. Interestingly, detect magic won't pick up on your familiar (again, that's what detect good and evil is for), but it will find a pre-placed clairvoyance sensor, or one that appears while the spell is still running. So there's a point for your familiar.

Of course, if the target has access to both these spells, they will certainly employ them both if they want to ensure their privacy. But if they have access to both and only enough resources to use one of these two spells, it will be a judgement call - do they feel more likely to be spied on by a familiar or by clairvoyance? Since clairvoyance is the higher level, they might play the odds and say a familiar is more likely and opt to check for that.

Once your campaign has advanced to the point that your targets are capable of Leomund's Tiny Hut or Mordenkainen's Private Sanctum, however, they will first sweep the area for hostile creatures like your familiar, and then put up one of these divination-blocking spells before having their sensitive conversation, in which case neither a familiar nor clairvoyance will be of much use to you.

Answer 6

It's much harder to detect and gets anywhere

My wizard has both these spells, and has used them both. In my experience, in general you are right, the familiar is more versatile and much more economic to use in terms of spell slots. You can even cast invisibility on it, which is still cheaper than Clairvoyance and avoids some of the issues with detection. I use it much more often. However, there are three major, practical benefits to Clairvoyance/Clairaudience, that the familiar cannot match:

• Remaining Undetected. This is by far the most important one. Your comparison is not representing what you are up against normally: most targets do not have Truesight, but they do have normal sight. That means they normally will be able to detect your familiar sneaking around, while clairvoyance creates an invisible sensor, makes no noise and needs no stealth to remain entirely undetected in nearly all cases. This vastly superior, if you want to spy without your target becoming aware of it. (Even with invisibility, a familiar still needs to make stealth checks).

• Access. The way we play it, find familiar says "you can cause it to reappear in any unoccupied space within 30 feet of you" so we allow it to "pop in" on the other side of walls or closed doors (If you don't, this point is much stronger for Clairvoyance). Still sometimes, you cannot get that close. If you want to look into the vault deep underneath the manor, with a closed door, you may not be able to send or pop your familiar in. But you can cast Clairvoyance, as long as you know where it is (which you maybe were able to figure out by sending your familiar in to scout until it hit that door).

• Range. You mentioned this yourself. One mile is a much longer distance than a mere 100 feet. In a city adventure, you can easily cast this from your inn or tower, and spy on someone entirely elsewhere in the city. You can get to pretty much any place in a large castle or dungeon.

Often a combination of these is where Clairvoyance shines: you need to get into a closed room, and without being detected. A spider popping in out of nowhere is pretty suspicious. Clairvoyance will do what you need.

If you have leftover spell slots in the evening (or in the morning, before your spells refresh), then there is really no material cost to burning a few unused higher level spell slots. I happily spam scrying now in such situations.