This story is about a person in a sort of technologically advanced secret government organization that is basically SCP.
The organization is very advanced and, in most cases, can revive dead people.
I haven't yet published a chapter in which any character dies and is revived, but plan on doing it a lot later on.
How many revives is too much?
Bit of a world building answer, but in a world with fictional aspects it is best to create some ground rules the characters have to abide by (in my opinion it's always better to first create the world, then the characters and at last the story).
Make it imperfect.
Each time a character is resurrected, the character sustains unfixable (mental) damage, that way you can justify restrictions on how many times a person can (legally) be resurrected seeing they will eventually become dangerous. Or damage to the heart that eventually becomes too much to be resurrected.
Scarcity in resources.
The resources are so hard to get that it becomes too expensive to keep doing it without good (financial) reasons. Or make it a trade issue, you require somebody else to die to bring somebody back...this would make it harder to do so (and when it comes to moral implications you can justify it by using criminals as sacrifice).
By having such rules in place it would become easier for you to decide when it becomes too much. Be it due to the moral conflicts or financial restraints the main character has to deal with.
It significantly lowers all the stakes in a narrative when death isn't permanent. Even once is enough for the audience to no longer take death seriously as a threat. That can raise significant challenges for you, as a writer. You're running the risk of building a cartoonish, video-game universe, with lots of violence and gore, but no lasting consequences --and accordingly, no way to make people care. So, you'll need to find other ways to build tension and uncertainty into the narrative.
Some of the ways other writers have dealt with this problem are by putting a hard limit on the number of lives (Jumanji: Welcome to the Jungle, or The Lives of Christopher Chant). In other narratives, dying comes with significant costs (memories, mental health, pain, resources). Or, in other narratives, permanent death is still a possibility under some circumstances.
Bring them back as much as you want, just make sure that they have other conflicts, motivations, things they fear. One simple way to do it is how they did it in Edge Of Tomorrow.
So, don't your characters remember dying?
I'd think the memories of the pain, shock, and horror of a violent death would deter people from dying more than necessary.
"Too much" is when your characters begin to hate the whole cycle.
There is no fixed answer to "how many revives is too many" because how a character's resurrection comes across to the reader is entirely dependent on context. If the revive system is just there to allow you to kill of and resurrect characters, thus eliminating any real danger from your story, ONCE is too many. But if the revive system is part of a larger world building system, and there are still things at stake, the answer is "as many times as you feel necessary."
As other answers pointed out, it is all dependent on what the consequences are for the characters, and the way that the resurrection is worked into the plot. Others have mentioned "Edge of Tomorrow" as a good example of seemingly infinite revives that don't deminish (and in this case are actually a keystone to the plot of) the story. I would add the netflix show "Altered Carbon" as another example. In that universe, normal death isn't necessarily permanent, as you can just be rebooted (but there are a lot of different factors that affect whether you will be or not, such as economic status, and also some consequences even if you are, such as potentially having to adjust to a new body. all these things help keep the whole narrative engaging.) Additionally, there is a form a death still that IS permanent, because if the part of you that is used to reboot you is lost, you're gone for good. So in this case there is a system that allows for supposedly infinite resurrections, but there is still a lot at stake and still a risk of permanent death.
To summarize: Context is everything. Set things up wrong, and you'll lose your reader's investment in the story. Set it up well, and you can resurrect as many people as you like as often as you need without losing the reader, because you have other things at stake to keep them interested.
One rule I’ve created in my own work no matter how agonizing it is for me is:
I am never ever allowed to bring my characters back to life.
For me this answer is pretty simple. It might be different for other authors, but my whole problem kind of centers around death. The antagonist is killing everyone, which is why they need to stop her. If they can bring people back to life then death has no meaning, and the antagonist literally just punches them every once in a while. Resurrection makes my whole book pointless.
For you however, resurrection is a part of your story. If people are killed, have that happen only once in a while because we know what is gong to happen and the killing part is only a setback. It’s not meaningful.
I am surprised that no one has mentioned this one.
What did they miss out on because of the resurrections?
If you were assigned to protect a target and jumped in front of them instead of dragging them to safety and was killed as a result, did your target survive? Maybe without your sacrifice the target could have survived but instead they lost your protection and died.
Knowing you had resurrection can change your actions and make you more reckless. Despite being able to revive, the tasks you leave unfinished, consequences of recklessness, and the items you may leave on your body can all be great reasons to try to survive.
Many questions like this can be answered by taking Sanderson's First Law of Magics, and labeling your particular technology as "magic":
Sanderson’s First Law of Magics: An author’s ability to solve conflict with magic is DIRECTLY PROPORTIONAL to how well the reader understands said magic.
Its really quite the incredible writing tool. It works for anything. You can apply it to "resurrection" or "making toast." If you solve conflict by making toast, you better hope the reader understands it!
Most likely you are using this resurrection as a tool to resolve conflict. I say this because you're questioning "what is too much," and that's a good sign you're concerned about this too. So you need to make sure that your readers understand enough of this magic.
Obviously there are rules to something like resurrection they will need to understand, but the most important understandings they will get about such a thing is in the show-don't-tell category. A tool which can resurrect people is a massive culture shaping force the likes of which have never been seen in all of mankind. Show it. If your world treats death like we do, multiple resurrections are going to start to feel cheap very quickly. On the other hand, if resurrections are part of the culture, you are going to see whispers of it in every single corner of society.
If the resurrections are limited to a small class of individuals, they will be the ones whose culture is completely underpinned by this capability. Others will be affected by the need to resolve this "unnatural" power.
Case studies I would consider:
Have you read Endymion by Dan Simmons? People are routinely resurrected using a "cruciform" attached to their body. Space travel actually involves no protection against G - indeed ships are designed to accelerate as hard as possible and pulp the occupants almost immediately. The resulting bloody mess is then resurrected at the other end. Ships can only go so far, so long missions can involve lots of deaths and resurrections.
It probably isn't a spoiler to say that the "cruciforms" turn out to not be a good thing.
The number of resurrections isn't a factor in whether the book works though. However the fact of resurrection existing certainly is a key element of the story, and it should be in yours too.
I'm going to post the complete opposite of A. bakker's reply, basing it on The 6th Day
As many times as you like
Make that a feature. Make everyone completely blasé about death. The tension comes from the destruction of the technology to do it, not from any inbuilt weaknesses of the resurrected characters.
The realisation of the potential of permanent death from characters used to treating it like a minor inconvenience is pretty powerful.
Also explored in some Culture books, where members do not store themselves before risky activities as a low tech "kink".
There are alternatives to death to consider. There can be meaningful consequences that don't involve death. For example, a character could break a bone, lose a super power, lose a close friend, or be disabled in some way. This increases the challenge for the character, lets the antagonist have some kind of a victory, and lets you have meaningful consequences without having to revive a character.
There's multiple ways to have permanent consequences without killing a character and requiring a resurrection.
I'm surprised this hasn't been mentioned here, but this can and does happen in our current world with current technology, to a certain degree.
While the line dividing life and death is one that you and I might hope to only ever approach once, there are people suffering from drug addictions who play hopscotch with that line. They have better odds of crossing back to this side if there's somebody with Narcan nearby. In some places, local government agents ("very advanced" is arguable) are the ones carrying and delivering that revival treatment.
SCP Foundation website has this.
The Samsara Mobile Task Force is comprised of 4 semisynthetic individuals who can be restored from backup copies or regenerated, apparently indefinitely. As I understand it, individuals restored from backup do not have memories of the mission on which they were killed; they are brought up to speed by their comrades who survived the mission, if any. Individuals might be terminated and restored from backup if they are corrupted somehow, infected by contagious memes and so on.
I think being revivable is either a one time amazing thing (Bible style) or a recurring possibility (done in the above SCPs and many other fictions; I think of Highlander). You can get energy for your writing with interactions between revivable entities, their memories, experiences, and altered attitude towards death.
Depending on the rules for restoring, you could restore from backup while the original (perhaps thought to be dead) survives in some fashion and shows up later. Or you could produce a legion of one individual from backup. I think the Samsara force members are made of special stuff and must bring back some piece of the individual to be restored, because otherwise I am sure they would make more; these folks are useful.
Also there is potential energy between nonrevivables and revivables - one SCP has the reaction of a team being sent in alongside the Samsara force. This other team knows Samsara is sent when there is a high likelihood of members being killed.
Until you're ready to publish a character being revived why not look, for instance, at any dying/reviving movie such as Groundhog Day, at Doctor Who whose regenerations are supposedly limited, or at the almost-endless Riverworld saga where large numbers of characters die and are revived every day?
Come to that, why not read Tolkien's On Fairy Stories, from C1935 and still taught today?
– Robbie Goodwin Oct 25 '20 at 00:59