Squats, presses, and benches are obviously sets if you don't rack the bar, since you're not resting while it's on you. Deadlifts I consider as sets if you don't let go of the bar between reps.
On heavy DL days, sometimes it feels like it takes me a long time to reset between reps. I've never timed it, but I'd guess that it's somewhere between 15 and 25 seconds. Although subjective, when does my set become 5 sets of 1 instead of 1 set of 5? 30 seconds between reps? 45 seconds?
Squats, presses, and benches are obviously sets if you don't rack the bar, since you're not resting while it's on you. Deadlifts I consider as sets if you don't let go of the bar between reps.
When does a set of 5 become 5 singles?
When Does a Slow Set of 5 Become 5 Singles?
Rest between reps within the set
I'm sure there are others, but those are the ones I found in a quick search.