Want to feel like an ancient hero? Worried about devilish assassins? Thankfully, even today there’s a solution from the medieval times that can help. Wearing leather armor was a common practice for men of status and warfare in the Middle Ages, from the 8th to the 15th centuries. Often times, the political agendas of feuding European and Asian lords required that there be some practical protection from common threats. A disgruntled soldier might end his lord's career, if he did not properly clothe himself on the field.
With all that said, here are the different pros and cons of wearing leather armor:
1. Protection from Assassination - Particular in the age of chivalry, there was often a poorly developed system of justice. Powerful barons often plotted against each other. A stabbing with a dagger during a night time stroll, or worse could possibly occur, particularly in large cities such as Paris, Tokyo, or London.
2. Protection from Battlefield - Metal armor was quite heavy, but no soldier would want to go out on the field without some kind of protection. Leather armor offered a balance of some protection, and a lot more flexibility for combat. A leather armor soldier could march farther, and if a knight lost his horse, he could walk easier if not encumbered by steel plates.
3. Ego - Let's be honest, most soldiers wanted to look the part. Wearing the leather armor could make a simple trade salesman look like something special. Many citizens were part time guards, so having something cheap to put on if their city was attacked was a useful purchase.
4. Price - Unlike metal armor, which required the skill of a highly trained blacksmith, it was much cheaper to fabricate a cow hide suit for protection. A soldier with a small budget would want something that kept him safe, but not in debt.
1. Hot - Like metal armor, leather armor added to the temperature of the soldier. While in Northern climates, this could be an asset, in southern climates such as Mexico or Vietnam, it would bog him down greatly.
2. Not as Safe as Metal - Metal armor was the highly prized symbol of being a knight or squire. Metal armor was very expensive, and very safe. Leather armor could be sliced through with a quick and powerful sword blow. Once effective crossbows and then gunpowder came on the scene, most soldiers completely discarded their armor because of its uselessness against projectiles.
3. Rarity - Although easier to make then metal armor, leather armor was still something that the average man probably could not fabricate in a day. This tended to raise the price. Clearly, this isn’t something a common villager could have in his war chest.
4. Weak Compared to Modern Technology - Since the invention of plastics, Kevlar has come on the scene as a modern and stronger substitute for leather. Many police officers wear it today. Modern Kevlar body armor can resist a small caliber bullet fired from a close distance. This is something that leather body armor cannot do.
Source: The Pros and Cons of Wearing Leather Armor