That you know what a team is capable of? I've heard people say week 4, I've heard people say week 6, and I realize that there isn't a one-size-fits-all answer... But I still find this interesting. To make the question a bit easier, I will rephrase...
Barring significant lineup changes due to injury/other reasons, when do you think that we will know what this year's Packers are capable of? When will we know their strengths, weaknesses, how well people work against different offenses with the 3-4?
I'd say by week 3 or 4 we should start to get an idea, but that by week 6 we should pretty much know who this team is.