It’s a delicate balance. How long do I wait between sets of heavy exercise? Focus on how you recover, not just an arbitrary amount of time.
The most common mistake in strength sessions is the lack of recovery between sets of heavy lifts. When I coached classes I constantly had to slow athletes down or they would essentially begin their next set as soon as the first was completed. Instead of 3 sets of 4 repetitions they would essentially do 12 straight reps and be done.
The issue with this is that the athlete is not able to do the amount of weight they could if they had taken time to recover between sets. However, if you wait too long you also don’t get the right effect on your muscles. I recommend that you use your breathing as a guide for how long to wait between sets of movements instead of a set time.
After you complete a heavy set (5 or less repetitions) get into a recovery position. Either sit down or lean over with good posture. Begin breathing using your belly, your chest, and shoulders. Once this feels forced begin to simply use your belly to breathe and slow your breathing rate down slightly.
Continue this until you can complete 3 exhales in a row that last at least 7 seconds. At this point you should easily be able to breathe through your nose in and out. Now you can begin getting ready to lift again. Following this breathing pattern and getting into a good physical position will help you recover faster and help you adjust as needed once the weights go up or feel harder.
Focus on recovering, not time, and you will accomplish much more during your session.