RE: El Irlandés: La historia de una confesión. // The Irishman: The Story of a Confession.

I've been planning to watch this since it was in the making but I never did.
I love Scorsese and the cast all together is marvelous, however the 3 hour long movie puts me off.
Do you think that those 3 hours were monotonous or necessary for the plot?
I believe deep down I haven't watched it because I don't want it to be a mess...