Let's sum up the different armour crafting recipes depending on the kind of material and the piece desired. You'll notice that the layout is very simple and only changes in terms of the material from which it is made:
(cannot be crafted outside of the creative mode but can be found in dungeons or from certain NPCs)
Of course, the defence points of a piece of armour vary depending on the quality of the material as well as the area it protects. As such, a leather helmet is a lot less protective than an iron chestplate, for example. The level of protection goes as follows:
Finally, these pieces of armour are not eternal, the following table shows the durability points of each of them. These represent the number of hits a piece can take before giving up the ghost: