How much recovery time would a superhero without healing powers need after a typical mission? Should I include downtime in my story as necessary for going out again?
It feels like I write this a lot, but in this case, it is extremely contingent on a long list of factors.
The first one is, if they were injured. This one should be obvious, but a character who’s been seriously injured will need to recover from that before they can safely return to the field. This is also (probably) the only time a character’s rapid healing would be useful for this discussion.
Downtime is necessary. Without it, fatigue will lead to injuries. There’s no mandatory timeline for how much downtime you need. It depends on what you’ve been doing, and how much strain you’ve been putting on your body and psyche. Regardless, you’re going to need to step away from that and recover before going back in. I’m being vague because that’s life. It doesn’t matter if we’re talking about your day job, or superheroics.
The hard part about figuring out how much downtime you’ll need is there’s no immediate penalty for ignoring it. Things like sleep deprivation can stack up over time, but it is something your character could put off, “in an emergency.” This can become a problem if your character is ignoring things like muscle aches or minor fatigue. And, it is entirely possible they’d put their mission, or the safety of others ahead of their own comfort. In extreme cases, they may even be ignoring actual injuries to get back into the field. This is a superhero after all.
If your superhero is engaging in direct hand to hand, the necessary downtime to fully recover will be at least a couple weeks. That said, this is something you can afford to abbreviate without risking the audience’s suspension of disbelief. This is one of those things that has become baked into the superhero power fantasy, to the point that it’s, practically, a genre convention. Your characters recover from physical fatigue with inhuman speed because, “superheroes.”
On the other hand, it is entirely reasonable to chart out a character gradually wearing themselves out by not having any downtime. As mentioned, this is natural behavior for a superhero, and punishing them for that behavior is entirely reasonable. The only thing I’d caution you on this subject is making sure you’re consistent. Don’t have one character who goes out every night without a problem, while having another who’s falling apart, unless their powers justify different outcomes.
There’s no hard and fast rules for how you need to itemize this, or if you even want to cover your characters’ downtime at all. The normal advice is, if a scene doesn’t advance the story, cut it. Downtime is incredibly vulnerable to this. It’s often ancillary events that have no relevance to the plot as a whole, and can be safely ignored. You might write some as a character study, but (most of the time) it isn’t relevant to the story you’re telling, so out it goes.
Now, it’s entirely possible to have a story where there are significant elements explored while the characters aren’t out there doing their jobs. In cases like that, downtime may be the story. It’s also possible you’ve got characters who take work with them wherever they go, so things that happen in those moments are still relevant to working out the plot. Downtime can also be an opportunity to see how your characters interact with other people in their lives that they don’t work with. There are a lot of ways you can use scenes like this, but there’s no credible rule saying that you must.