Do you complete a game before going on to the next one?

[Ail]

I was like that last gen.
This gen I actually spend more time on each game and for the first time find myself tackling the harder difficulty modes, I used to play a game in normal and was done but for example I have cleared every single mode in DMC4 and am in the process of doing the same in Uncharted ( although I am getting my ass kicked pretty badly in crushing mode right now).
If I had a 360 instead of a PS3 this would even be worse as I know I would be an achievement whore ( heck I have 1000/1000 accomplishment in DMC4).