A small book I read years ago mentioned said Bruce Lee would do 1k daily as an example of self-discipline. It was in addition to all his other training, this was just the baseline.

Once you can do 100 in a set though, that's just ten sets throughout the day. Totally doable if your employer can tolerate a sweaty employee.

I've learned it is very important to think about achieving this output in small batches (sets) as you mention. For instance on Saturday I did 527 pushups. I did a set of 30 in the morning, and then did 400 on the soccer field with my friend Charlie (the neighbor mentioned in post). But we did these in 16 sets of 25, every five minutes over the course of our kids' soccer game. Then I came home and figured since I was so close to my PR (525), I might as well grind out another hundred in order to eclipse that number. I wound up at 527, doing the last 97 in batches of 15, 10, and even 5. I actually think I did the last two in sets of 1 lol because I was so wiped out!