Unless I really don't like it (last game of this type was Skyward Sword), I'll play through the single player campaign or story mode or equivalent until the end of every game I start. How many side quests and whatnot I do along the way depends on how interesting they appear to be at the time.
Once I've finished a game, I'll move onto something else, rather than keep playing it until I get bored of it. I just replay games that I enjoyed again and again later on.
Once I've finished a game, I'll move onto something else, rather than keep playing it until I get bored of it. I just replay games that I enjoyed again and again later on.