There is something to be said for having everything happen at once.
Often we think of the climax of a book as the place where everything comes together and starts happening at the same time. However, we shouldn't necessarily restrict ourselves to the climax; layering can be beneficial at other points in a story as well.
I mention this because of my own experience. I had a sequence of events in my WIP as follows: the protagonist had to go to a political event; thereafter my bodyguard character had to follow a nefarious character to prevent an assassination; thereafter my bodyguard had to come home and find a conflict going on between the master and mistress. It wasn't bad, but when it came to dramatizing the whole thing, I found it was dragging. I was struggling to get the protagonist out of previous plot points and over to the political event. I was daunted when I tried to imagine all the details of the political event. Then I couldn't figure out how to make the opening of the prevent-an-assassination sequence different from all the previous interactions between servants that I'd been working with (I try to make every interaction unique - something I'll be writing about soon in another post).
Over this weekend I realized what the problem was. Everything was strung out, all the events coming one after another like beads on a chain. That simultaneously put too much importance on each individual event, and made me work too hard to keep them connected.
I therefore decided that as many things as possible needed to happen at the same time.
I can get away with this in my novel, because it's supposed to be complex. It is certainly possible to overload a scene with too much stuff. However, if you can find a way to concatenate instead of stringing, the result can be amazing. In the case of the sequence I describe above, I decided that the political event and the assassination attempt had to happen at the same time. This accomplished several useful things for me.
1. Because the assassination attempt had to occur in a specified location, I suddenly had a place to put my political event that was more effective than the white-room-ish space I'd been fighting against previously.
2. Because the new sequence placed both my protagonist and my bodyguard in the same location, it allowed me to do a direct point-of-view handoff (I love those).
3. Because I could do the point-of-view handoff, I could shift to the bodyguard's perspective early in the political event, thereby making it unnecessary for me to elaborate on all the details of the event. In fact, the ceremonial details of what's going on are much less important than the bodyguard's attempt to foil the assassination. Layering allows me to place focus on the more important element and stick the less important element in the background.
4. Suspense went through the roof. Instead of having the bodyguard out attempting to stop an assassination on his own terms, he's right in the middle of a public event trying to figure out how to save the target from the assassin without having any means to reach the assassin (who is hundreds of feet away) or the target (who is at least fifteen feet away).
5. Consequences also became much more dire. The bodyguard won't be able to take action without hundreds of people seeing him, and this will result in entanglements that delay his return home, providing a perfect reason for him not to be where he needs to be when the conflict between master and mistress begins.
It's worth keeping an eye out for opportunities to do this. Especially if you are being told by critiquers that your story is wandering, that the pace is slow, or that it's one thing after another after another, consider whether layering might be the right answer.
You might also want to look out for this if you're trying to figure out how to shorten a work. What if you feel like you've taken out as many words as you can and the book is still "too long"? Maybe you're aiming for 90-100K words but you're stuck at 127K. Usually at that point it's the structure of the story which has to change - and if you can take a step back from your outline and create clusters of events that can either closely follow one another, or happen concurrently, then the layering effect will save you a lot of words that can't be "pulled out" any other way.
It's something to think about.