For what the originals cost, is it really worth not changing it? I've seen a couple leak. Not many but if there's £40 worth of oil splashing around in there, do you really want to drop it again? Get the 2 washers and filter at the same time and you're sorted.
I think I paid something like 20p for the washers, at that price why not buy a supply so you dont have to take a trip to a ducati dealer next time you change the oil
I never knew you were meant to replace the washers. On the monster I just sold I did 3 oil changes and never changed them. Not a drop leaked from that.
At that price though I may start doing it just for the sake of it.
I replace all of the drain washers (gauze plug and the drain plug) evertime I change the oil. I order my filters from italia and they always chuck in the washers for me.
I have to confess that in all the years I've done my own oil changes (since 1976) I have only changed the washer once - and that was when there was a small leak. I've never found it a problem, but I was recently berated by an engineer for not changing the washer. I figure if it don;t leak it must be doing it's job. With regard to copper vs ally - provided it's soft enough to compress and seal I don't suppose it matters.