Yesterday I divided Terran macro mistakes into five simple categories. I also covered the first three of those categories: SCV production, avoiding supply blocks, and unit production. Today I will discuss infrastructure development, which I see as a more complex area of macro. It should be noted that this section can easily be broken down into more categories, but I see that as unnecessary and overly complicated for all but the highest level of players.
Infrastructure development itself is easy to understand, but can be difficult to use. Simply put, every building you place as Terran that is not a missile turret, bunker, or sensor tower is developing your infrastructure. This means that almost all buildings expand your capabilities in some way for the duration of the match (or until the building is lost). Some examples are:
Command Center: Expands economic and tech options by unlocking mineral patches and gas geysers. Also expands economy by allowing for increased SCV production. More C Cs = More Money Refinery: Expands tech options by allowing for increased gas income. More Refineries = More Gas Barracks, Factory, Starport: Unlocks and/or expands unit production. More Barracks/Factory/Starport = More Units Tech Lab: Expands unit production options and unlocks unit upgrades. More Tech Labs = More Unit Options Engineering Bay: Unlocks and expands unit and building upgrades over. More Engineering Bays = Stronger Units/Buildings
Each of these has a different purpose and the key to developing a good infrastructure is balancing all of these appropriately. For example, if you have too many workers or too few, you should probably build a command center. If you want to play a longer game, you should likely build refineries and engineering bays. If your army is too small or you have too much money, you should consider adding more barracks/factories/starports. All of these are infrastructure based mistakes.
These concepts can feel very obvious and simple, but the difficulty and complexity comes into play when you try to make all of these ideas work together in harmony. These elements must be balanced in order to safely continue the game. When any of these is sacrificed, a weakness appears that can be used against you. This is shown most easily when looking at very greedy or very aggressive (cheesy) play. When you are being very greedy by placing many command centers and avoiding unit production, a slightly aggressive player can easily kill you with an attack that normally wouldn't succeed. In the same fashion, an overly aggressive player can easily be defeated by one that is defensive, who develops tech and economy at a standard rate while maintaining unit production. I'm not saying these strategies are bad, but I will say that they bring a random factor into the game that should be avoided when attempting to improve.
Thankfully, we don't have to put much thought into what a properly developed Terran base would look like, as we can simply watch a games and replays from high level players who are following these principles and copy what they do. All we need to be concerned about is identifying and recording the mistakes when we watch our own replays. It is important to use replays for this as it allows us to separate this mistake from others more easily. For example, as stated above, when money is high we should add unit production buildings. But what if we aren't using the buildings we already have down? That would be a unit production mistake, rather than an infrastructure mistake. As another example, it would be a mistake to have too many buildings down. That's easy to feel in game, we don't have the money to spend to keep all of our buildings active. But what if when we check the replay we realize that either we weren't constantly making SCVs, or we had too many SCVs for our number of bases. The first is an SCV production mistake, while the second is likely a completely different infrastructure mistake, failing to expand properly. As you can see by now, these mistakes can be easy to misinterpret, and must be examined carefully in a replay, rather than making an assumption about the problem at the end of a game.
The last thought I'd like to leave you with is that while these mistakes can be adjusted for in game, they can never actually be fixed. By the time you realize that your money is too high, it will take you a full minute and a half to two minutes to get the necessary buildings down. This means that your buildings are two full minutes late. The goal is to identify outside the game when these buildings should be placed, and simply recognize those situations in game. This is why we simply copy the build orders of pros and execute them to the best of our ability, rather than making the decisions ourselves. This way we can grade ourselves toward a very specific ideal for each game, rather than a theoretical perfection.
Tomorrow I'll move on to identifying and recording tech development mistakes.