Character deaths should never be treated lightly.
I know that in superhero books, especially from Marvel and DC, death is hardly ever permanent. In the 80s it was “they're not dead unless you see the body”, and then it was “You're not dead unless you're Bucky dead,” but with the return of James Buchanan “Bucky” Barnes as the Winter Soldier, that's no longer true. There are few characters that stay dead anymore.
There are reasons for this. Generally, characters have champions in writers or artists who have always wanted to draw them, and so a way is found to bring them back. Or the character was killed as part of a plan, and bringing them back was also part of that plan. Death in superhero comics became cheap, lessening the story value. Where are the ultimate stakes if death doesn't mean much?
Death means something. Or at least it should. It should be done with both forethought and purpose. Death should have an impact on either a character (one who isn't dead) or the story, and hopefully both. This is why death should be rare in comics. It isn't, but it should be.
And don't think you can get away with destruction and not cause death. The Avengers movies are great for lots of destruction, but you see very few deaths. Man of Steel had lots of destruction as well as very few deaths. You have characters like Captain Cold who go around freezing people—regular people—but we never really seem to internalize those. They're dead without us really realizing it.
Be better. Treat character death with the gravitas it deserves. Don't let death become a revolving door. If you have to do something traumatic to a character, own it. Anything less cheapens not just the story, but the medium itself.