Remember, fewer reps (up to 10) x3 with heavier weights is better than multiple reps (10~20) x3 with lighter weights.
"Remember, fewer reps (up to 10) x3 with heavier weights is better than multiple reps (10~20) x3 with lighter weights."
That is an irresponsible statement. You don't know anything about the person's age, overall health or fitness aims.
What do you mean better? Better for what and in what way?
If I were training someone who was in good health and just beginning to trains with weights I would advise the higher reps and limit each workout to four or five exercises.
Depends. The goal is to work the muscle to failure. Using a heavy weight a few times doesn't engage all the muscle fibers before the initial ones tire out.
Since I'm not interested in building mass, but basic strength and endurance, I like to use a weight that is about 1/2 of my goal weight to warm up with a couple of sets of 15-30, then one set of the goal weight.
Since it is good to mix things up, I also like to sometimes go low weights, high repetitions (20-50/set) for a few weeks, or a few weeks of high weight/low reps (5-8).
Increasingly, I find myself using body weight type exercises, with a step ladder of repetitions to work to failure. If I do that with push-ups until it becomes a strain to do 15 push-ups, then the next day I'll feel like a whipped puppy.
Now for the real question - why do I work to feel like a whipped puppy?