Avoid calculating a unit’s cost based only on it’s (mass + energy) price. Instead calculate a unit’s cost based on what it costs you in future production through terms of “lost production capacity” vs “short term benefit”.
For example:
The price of seven and a half T2 Tanks is equal to the price of a single T2 power generator. The output of a single T2 power generator is equivalent to an additional T2 Power generator every two minutes. Two T2 Power Generator’s output is equivalent to an additional T2 Power Generator every minute. Three T2 Generator’s output is equivalent to an additional T2 Power Generator in forty seconds. Four T2 Power Generator’s output is equivalent to sixteen T2 Tanks a minute.
The price of seven and a half T2 tanks costs four T2 Power generators in just three minutes and forty seconds. Therefore, in three minutes and forty seconds your seven and a half T2 Tanks will cost you sixteen tanks a minute in lost production. The future price of each tank will be three and three quarter’s seconds of output. By expanding your economy you are lowering the future cost of each unit you build. It is important to note that seven and a half T2 tanks don’t build additional tanks or replace loses.
If you build military force, they must be used immediately before time depreciates their value.
