In real time strategy games, units are made using a resource which is usually collected by workers. In Starcraft 2, the resources available are Minerals and Vespene gas. A good economy in this case would be a scenario where you can always afford what you want to build without building up extra money. Because the goal of the game is to beat the other player, you always want as much as possible but no economy could possibly support that so we’ll shorten it to being able to produce out of available facilities.
A worker mines minerals or vespene gas at a constant rate, with one worker mining a mineral patch or collecting gas at a time. You notice that you start with six workers but there are eight available mineral patches to mine from, this is a clear indication that if you want to maximize your income, you need more workers. While only one worker can mine from a mineral patch at a time, you might believe that you only need eight workers to maximize your income off of this particular base. This misconception always leads to new players not building enough workers and getting steamrolled because their income was half of their opponent.
An important concept for maximizing income is, “saturation,” or getting the maximum amount of resource over a period of time. Because a Nexus, Command Center, or Hatchery can not be built next to a mineral patch, there will always be a travel time for the worker bringing back the resource. While the worker is traveling, that particular patch of minerals is not being mined which allows another worker to mine it instead. Because of this, full saturation on minerals would be two workers per close mineral patch and three workers per far mineral patch. A safe amount would just be three per patch, and with eight mineral patches that would come out to 24.
Vespene gas is mined only after an assimilator, refinery, or extractor is built on top of it for 75 minerals (25 minerals for Zerg because of the cost of the drone). Only one worker can mine vespene gas at a time so the same concept of saturating minerals applies here, where three workers per vespene geyser is required to get the maximum amount of gas. It is easy to see that you have eight patches of minerals mining five minerals at a time versus two vespene geysers mining only four gas at a time. This shows that gas is the limiting resource in the game, meaning that people will often get an excess of minerals. People often coin the term, “mineral sink,” for units or structures that require no gas to build to spend their excess minerals on.
So now you know that you need 30 workers per base to be fully saturated while only being able to build a limited amount of workers at a time. For newer players, the general rule of thumb is to never stop building workers. Always make sure that you have an SCV, Probe, or Drone being made and your economy will hardly fall behind unless your opponent takes an expansion.
An expansion is the acquisition of a new base, or typically the players, “Natural expansion,” or the closest expansion. By simple math, to get the best economy possible, one should always spend his or her minerals on workers and use the excess to build another town hall at a new expansion. This allows someone to potentially have double the income of someone playing off of one base. While this is a good strategy, it carries a lot of risk because it leaves you vulnerable and spread out. If your opponent invested resources in an army instead of an expansion, they could kill your expansion and workers, setting you back tremendously. We will go over appropriate times to expand in future guides.
On a final note, how do high-yield expansions work? If you were to look at them closely, each patch allows a worker to mine seven minerals at a time instead of five, a 40% increase but how much does that increase your income by? There are only six patches at a high yield mineral expansion yielding only six times seven minerals per trip of workers, or 42 minerals. A regular expansion has eight patches, yielding eight times five minerals per trip or 40. The increase in minerals in itself is not too large but the real benefit comes from the lowered cost of saturation. By having to only saturate six patches instead of eight, you save six workers which total 300 minerals.
We have covered most of the basics that make up an RTS so in the following guides, we will go over things very specific to Starcraft 2 such as units and structures.