Pull-ups and Chin-ups are perhaps the most frequently-used measure of men's fitness, and some form of them belongs in any fitness regimen. What's the difference between the two?
If you are in bad shape, you will not be able to do many, or even one. That feels pathetic and unmanly to most guys. I recall that my Dad had the habit of morning pull-ups and push-ups well into his mid-70s before work (worked until 76). He kept that part of his Basic Training going. He was naturally wiry and strong anyway.
Only the fittest women can do any because they have less native upper body strength and tend to have a higher fat/muscle ratio. Many middle-aged guys find their paltry pull-up counts to be deeply humiliating, and rightly so. Weakness is shameful for most guys, even more so than ignorance, for evolutionary reasons. In fitness training, humiliation and failure are always on the agenda. That builds character, victory does not.
One good test to assess your pull-up potential is to jump up to a bar and see how long you can hang with your chin at bar level. That is, in fact, a good strengthening exercise in itself for beginners. Count the seconds that you can hang up there before slowly collapsing.
Chin-ups and pull-ups test primarily back muscles, and secondarily arms and core. Three sets/wk is plenty. The technique is not to muscle one's way up with your arms, but to lift your chin to the bar by driving your elbows down with full power.
As far as I'm concerned, pull-ups can be viewed as either weight-training or as calisthenics. It's a body weight, multi-muscle group stress and, if 15 reps gets easy, just put on a weight vest to keep it challenging. Here's how to Do More Than One Stinking Pull-Up
Are kipping pull-ups cheating? It depends. Certainly anybody would prefer to do more dead-hang pull-ups if they could. They are hard. All exercise is agonizing, though, if done right. No pain, no gain.