That rule only applies to nobles.
If I recall correctly, I have been unable to buy a piece of armour *on my advy* because I already had one. I assumed that finding/making them was the only way to negate the one-per-character rule.
My advies never managed to accumulate more than two items, regardless of type.
Yeah, four is the most that I have ever had at one time, out of a total of 14 items (over about one and a half years).
