Going to revive this thread briefly, if only to say that I'm going to add the following to the front of the thread at some point later today: Section 3: Investment and the cost of build power In the long-term, economy management is about planning a set of investments, and balancing what you need to spend your resources on now against what you'll need to spend them on in the future. You will obviously need to invest your resources in units at some point, but many of your investments will be related directly to your economy. You'll either: 1. be spending metal on your ability to spend future metal production in useful ways. or 2. be spending metal on things that will increase your metal production. Point 2 is simple: you want more metal available to spend in future because metal is what you need to get pretty much anything done in the game. You should always be planning how you will increase your metal production in some way, and 80-90% of the time you should actually be building more metal production, whether that's through expanding T1 mexes across the map or through adding T2 mexes in your core territories. Point 1 is more complex. Your ability to spend metal is your build power, your ability to get things done in the game. While you don't usually want to have vastly more build power than you have metal production - build power costs metal to produce like everything else, and surplus build power is wasted - it is much, much better to have too much build power than too little. More importantly, build power costs energy to run. So with every investment in build power you also have to make a corresponding investment in energy production. This energy cost is in some ways a 'hidden cost' of building more engineers and factories. But once you understand that when you buy an engineer or factory you also have to buy the energy production to run it, you're well on your way to understanding how to invest effectively in build power. Some investments are better than others, though. For their cost, T2 power plants are the most productive means of generating energy, giving an impressive 1.852 energy output per unit metal cost, compared to 1.33333 for the T1 generator and 1.451 for the solar array. Solar arrays might have something going for them in that they can't be taken out by ground units, but in terms of raw power the T2 generator is the way to go. Likewise, as shown in the spreadsheet above, whilst assisting T1 factories is always a waste of build power due to the short production times of units compared to the roll-off times of the factories, assisting T2 factories with T1 bot fabbers is often far more efficient than building new T2 factories due to the high cost of both the factories and the units being produced. In fact there is a magic number of assisting T1 bots for each type of T2 factory, which represents the peak value-for money of investing in assisting bots versus building new factories. So: T2 bot factories should be assisted by 23 T1 fabrication bots T2 vehicle factories should be assisted by 19 T1 fabrication bots T2 air factories should be assisted by 16 T1 fabrication bots T2 naval factories should be assisted by 53(!) T1 fabrication bots (if you can build it close enough to the shore) - OR 21 T1 fabrication subs (the most cost-effective naval build unit) These numbers assume, of course, that the assisting bots are working perfectly (which they don't, always) and that you can actually fit them around the factory in a way that doesn't impede the roll-off of units. They also assume that you're powering everything with T2 generators, and that you're building combat units rather than the much cheaper engineers. Still, these numbers represent your best plan of investment in build power if you want the ability to produce T2 units, especially when you consider that T1 bot fabbers are more flexible than factories and can be dragged off the line to spam up turrets to counter imminent threats. EDIT: Nope, this makes the front post too big. Well, damn. I'll just point people from the front post to this one.