Yeah. There were a couple parts that were.. really RARE drops, and only specific monsters would drop certain parts. I remember browsing the SotNW forums one day about Catherine's parts out of curiosity (I had found a stance ring for Catherine on the very first day after I installed the game, and wanted to find out how much it was worth. Didnt have the deposit for that amount at the time anyway .__.), and it seemed some people were able to collect the parts in a MINIMUM of 3-4 days, if they were.. really lucky, and hunted all day .__. But it easily took about a week or longer for the majority.