The Knights of Yore, as portrayed on our television screens, and at cinemas, these days, probably bear little, or no, resemblance to the actual knights of Medieval times. The romanticism attached to the Knighthood, the Knights and their chivalrous acts will be totally exaggerated and idealised. Life was hard for all people in the Middle Ages and it was difficult even if you were a knight. Knights of the Middle Ages were trained for many years before they were classed as fully fledged knights and their lives were tough. Their clothing would have changed, as they moved through the ranks to reach their status as Knight.
On the whole, even for everyday folk, clothing would have been cumbersome with no light, breathable, man made fabrics around. Laundry would not have been easy and so the cleanliness of clothing probably left much to be desired. Knights came from noble birth and their task in life was to protect and defend their Lord, following a Code of Chivalry. For combat a Knight wore a heavy suit of armour. Suits of armour were expensive to make and also took a great deal of time producing. I suppose that it would also take a knight some time to get used to wearing such a suit. A great deal of strength would be required to be able to wear this armour. even for short periods of time. This Armour was made to measure and needed to fit perfectly, otherwise the results could be dangerous and disastrous.
In the early Middle Ages Knights tended to wear padded clothing covered with chain mail. This was basically links of metal covering a leather garment. The armour consisted of chain mail and metal, with many layers. Heavy, dense pieces of metal were made to cover such vulnerable areas of the body as the chest and heart. This clothing was flexible but did not offer the necessary amount of protection. With time a suit of armour was developed that offered greater protection to the whole body.
The Knights suit of armour was adapted over the years depending on what had previously been successful and what had failed. Of course type of protection evolved as weaponry moved on and new weapons were invented. Each suit of armour also showed how important the knight was. The more important the Knight, the more impressive and expensive the armour. Finally, a vital component was a metal helmet with a visor, offering some protection for the skull and eyes, for example. When a Knight was not fighting or training he would wear the usual tabard and leggings, of the day, but would still wear some chain mail as there was always the risk of attack.
A full suit of armour, with all its undergarments, would weigh a massive amount, be hot and sweaty and be very cumbersome. Every part of the Knight's body would be covered, including hands and feet. Such a suit would not make the wearer fleet of foot and their horse or steed would need to be a sturdy breed such as a Shire horse.