I don't know why people scout so early, I find it pretty useless. If you scout early you will see the opponent is building a barracks, spawning pool or gateway. Those of course are the pre-req buildings.

I think after the 10 minute mark is a good time to scout not before it. How bout you guys, do you find value in scouting so early?

edit: I meant to say 5 minutes.

I tend to scout as early as I feel comfortable with. It's usually dependent on the matchup and the map. If they randomed a race, I scout earlier than if they chose one. I will usually scout when my worker count is at 9 or 12 depending on the race i'm up against. I find that scouting will generally determine the game for me one or the other or at least is a major factor in my success or failure. When you scout early, you get a chance to check if they are doing any tricky strats (like proxying something) or get a general feel for what their build order will be (are they fast teching, fast rushing, fast expanding, or doing a standard build). You also get a chance to disrupt their plans and harass them early on. For example, attacking SCVs that are building a structure, preventing the building of a fast expansion and other structures by getting in the way, and just being a general nuisance in their base.

There is so much key info for you to use early on that you can adjust your strategy to, unless you're doing an all-in strategy yourself. You can also keep them pretty preoccupied by running your scout around their base until they decide to take the time to expose of it. =)

I also tend to see more constant scouting at the higher levels. What are other people's impressions?