I was never sure which items just need to be equipped and which actually had to be (U)sed to have an effect (e.g., Scarab of Protection, Luckstone). The lack of documentation for the game hampered me when it came to equipment. The game lets you put any item in any slot-it just doesn't always work there. My backpack is full, so I'm carrying a horn on my shoulder and a scarab on my belt.

As Mike Riley pointed out in a comment, identification applies to the entire class of item, so you only need to identify a Ring of Fire Resistance or a Staff of Striking once.

It takes far less than one dungeon level to fill up the backpack, so I would eventually resort to carrying items in the most unlikely of places before lumbering back to town to identify the unknown stuff and sell the stuff I didn't need. Equipment rewards were also better in the tougher dungeons.