Let's see. In tkd as a 15 year old was the first time this was expected of me, took me a couple of months to build up to it.
Then, in the worst school I was ever part of, from about seventeen years old to maybe twenty, 100 knuckle push ups was a requirement.
In fact, the only school I was ever part of that didn't expect this was a longfist class, because the teacher expected you to do your workout on your own time, you were there to learn the system. I was still doing this on my own. That was probably twenty years ago now.
When I was studying the system I do now, 100 push ups was under the minimum, while the numbers would get much higher on some days. His class is still this way.
Now, I generally do three minute rounds on the heavy bag, or, if not at home, three minute rounds shadow boxing, or, if a training partner is present, three minute rounds of either clinch work or pad work, with sets of 25 push ups in between on days I'm working upper body. I consider 100 a fine finishing point, and from there, if I have a throwing dummy or heavy bag present, I follow up on further breaks by squating and lifting the dummy or the bag ten times on breaks. I do 2.5 miles jogging five times a week, picking routes with big hills and using the hills to maintain consistent speed despite fatigue. Up until the last two weeks, I was also swimming 600-700 meters freestyle twice a week, which I hope to pick up again soon. A normal day of training, I'm doing twelve rounds, mostly due to time constraints, 18 is what I do if I have the time.
In my worst shape, probably about 5-6 years ago, I was doing a lot more than 100 push ups several times a week, while carrying probably 60 extra pounds. Once I changed my diet, it all got a bit easier.
From there I started using the pull-up bar. Currently, I range between 50 and seventy total chin-ups/pull-ups counting close grip. I'm hardly as strong as I will get at this, I just like to take it slow.
As far as abs, I have what I consider my minimum daily routine: 100 crunches, 100 reverse crunches, 100 waist twists, 100 of a particular side crunch. For anytime I have more time, I add to that 50-100 full situps, 50 bicycles(which, admittedly, is about my limit before they start tweaking old back injuries from work), power bombs, whatever.
On leg days, I do a lot of dropping moves that resemble squats. I do sets of 50-60 of each. In addition, when working rounds with a partner in clinch, we do 2-4 rounds of what we call dropsies, where with the minimum of setup each has to attempt a dropped stance move on the other, which tends to really get the legs.
I have worked a physical job most of my life. I'm used to being around guys who can do 100 push ups, who have to, because they might need to unload a truckload of 4x8 MDF at any time. As said already, 4 sets of 25 is not that much at all. Growing up, Joon Rhee and his 1000 push up thing were the typical goal for many tma schools.