Is it optimal to break up deep work periods? I understood that people don’t tend to work optimally after about a 45-minute period?

It depends on the individual. 20 minutes isnt enough time to get alot done. But if you are someone who only has 20 minutes to spare then yes. But i like to be able to get alot done bc once im no longer doing that my life has so many demands on me that i wont have time later to get back to tbat deep work i was doing.

I find that I work best for 45 mins or longer. I get into a groove and suddenly I’ve been cleaning or organizing for 75 mins or more. If I only work in short bursts I tend not to do as well.