In Bodybuilding the guys would do up to maybe 10-20 exercises per body part to sculpt the body for competition. Granted these guys are competitors and they do other stuff than just training to get as big as possible but also cut fat at the same time. For the average person and those who rely on building functional strength & health you don't need to do that many exercises to get the greatest benefit. In my training alone these days I do at least 20-24 Exercises for the entire body not for each area of the body.
Learning from guys like Brooks Kubik, he teaches that your best bet is to use a minimal amount of exercises for certain muscles however, you don't need to do a ton of different exercises but do very few and hit the muscles hard. When you utilize a few let's say for pressing, a couple solid pulls, 2-3 for the legs, some ab work using no more than 4 exercises and a few for the grip your total is right around 18-20 exercises all together but putting your heart and soul into beating them in submission. In Body-weight Training, you could isolate the muscles but for the most part you don't need to do a ton of different exercises but only a few that really hit the spots you need.
Karl Gotch once said that you don't need to do much for doing a lot; what that means is that you dont need to do everything at once but do enough to where you're making every exercise count. Push-ups, Squats, Core Work and Grip are the foundation and when you add pull-ups to the mix you don't need to go any further unless you have a specific goal in mine. Some people like to do hundreds of reps in the push-ups and squats, do a couple hundred sit-ups and leg lifts and do as much as 100 pull-ups but in reality that's only one way out of many others that can get you top notch results. Sure you can do a few exercises in circuits, you can do them with low rep schemes or go at random and see what you can do. I like to keep my reps to a minimum, I have done over 300 Push-ups & Squats in a single day plenty of times but that to me becomes boring and when it gets boring there's no excitement. That's where my current training comes in with Animals & Bridging.
I have over 30 Animals at my disposal in a workout and on certain days i'll hit all of them, on others only a few but I make the workout short and to the point because no matter what animal comes up, you'll be using your whole body one way or another and you can get exhausted within only a few minutes. The longest workout I ever did with animal movements is no more than 35 minutes and that's at advanced levels. With the bridging, I do a minimum of 4 exercises and do no more than maybe 7. Bridging Exercise when done properly doesn't need more than 15 minutes to really feel it, you'll notice it in less than a few. Last night all I did was the Wall Walking, Chest To Wall, Front Bridge & Back Bridge that's it yet had a major high, got every muscle worked, stretched my spine like crazy and felt very strong at the end.
The big point here is that if you want results in on of the best and highest forms possible, you don't need to do a lot of exercises to get the best benefits. Some things come in small numbers yet can create the biggest impact. Train accordingly and make the best of what you have and you will find that it's not always how long you can go, it's how you made an impact in the time you have.
Be sure to catch up on my site and find courses that suit your needs. These alone can turn you into a machine with little amount of time. There are beginner courses and there are ones that will take you to heights you didn't think were possible and most of the time, doesn't take more than 30 minutes a day to get top notch results. Stop on by @ ben-bergman.branded.me and take up on the best quality books, dvds and travel equipment in the world today.