A follow up question:

If I'm not mistaken, plate armor (especially "full") are very expensive and mostly exclusive to the royals or high ranking knights. I also read that most armors are personally made for the user, like tailored suits in the present time.

What are the common type of armors (materials) used if it's not made of plate? (Full, half etc.) What's the difference between the strength of the said armor vs plates?

Also, would this warrant the renewed use of shields?