It is Armor that makes a knight. It makes him close to invulnerable. It wraps him and binds him together, no, that’s duct tape…..but Armor is a big deal. Even today, people who want a well made set of armor will have to pay dearly for it. Some modern armors cost as much as $30,000. and it is common to expect to pay at least $4000 for a decent harness. Good armor fits a person well. It moves freely without binding through the expected range of motion for the style. Some work better that others for certain things. Don’t expect a jousting harness to move as well as a field harness, and don’t expect the protection from a lance to be equal between a field harness and a harness for the joust. One is optimized to face a mounted opponent with a lance, while the other is optimized for everything you might need to do in armor while in the field while balancing protection and movement.
Making armor is a time consuming process. Pieces must be cut, formed, punched, heat treated, polished, attached, articulated and strapped. There might be as many as 40 separate pieces in a gauntlet alone. The processes can be sped up some by modern methods, and many labor saving devices were used historically such as water powered hammers and grinding and polishing wheels. In fact, many are the same labor saving devices that I currently use in the production of my armor. The greatest advantages I have over medieval armorers, is a supply of high quality sheet material, and a cnc machine to cut it out for me.
Regardless how well the armor fits, it must be worn over the proper arming garments. even if it just maille, it needs the proper under armor garment to help protect you (and it). These garments may restrict your range of motion as well, and must be fitted to you very well in order to function properly.