Is your factory upgrade actually worth it ?

To figure out if an upgrade is a smart move or a waste of resources, we have to look at the Break-even point; the exact number of days it takes for an upgrade to pay for itself.

Cost Normalization

In order to assume a perfectly balanced market, we will consider the price of steel to be equal to 10 Iron (10 PP) plus 10 PP to manufacture => 20 PP.

The Math

To calculate the break even point in days, we just need to divide the upgrade cost (in PP) by the additional PP per day (+24 each upgrade).

A common pitfall is to look at the total PP and think that the investment pays off faster than it actually does. However, we should look at the Marginal utility: the extra production gained from that upgrade

Here is the calculated result:

Accounting for bonuses

Practically, most companies profit from a production bonus if located properly. So your investment actually pays off earlier than previously calculated.

effective increase = PP per day (24 PP) * (1+ bonus production percentage)

We will use the current bonus production of steel, 62.25%.

Here is the updated result:

With the bonus, the 5th upgrade takes only 82 days (2.7 months). This makes the 5th and 6th much more viable. the 7th upgrade however still takes nearly a year to recoup the investment.