One interesting factor that I rarely see discussed is this: Let's say a DevOps person does some improvement to internal tooling and a task that devs had to oversee manually now is automated. Every dev spent about 2 hours per week doing this task and now they don't have to anymore. Now, have we saved 2 hours of salary per dev per week?

Not sure. Because it totally depends on what they do instead. Are they utilizing two hours more every week now doing meaningful work? Or are they just taking things a bit more easy? Very hard to determine and it just makes it harder to reason about the costs and wins in these cases.

They have saved _more_ than two hours per dev and week. There's a compound factor and now code can be more reliable (less outages or emergencies fixing bugs) etc. Also having a sane working environment helps engineers not quitting, which is very expensive if they are replaced.

You've freed up 2 hours per dev per week so they can work on something else that might generate profit. Even if they goof off for an hour, that's another hour doing something useful that they weren't doing before.

You've also possibly saved some money by automating a task that was previously manual, reducing or eliminating human errors that could have compounding costs.

And as someone else pointed out, you've made the work environment a little better by not wasting the devs' time on a silly manual task, which might reduce turnover.

The freed-up time question is answerable when the work has clear metrics. A model test suite dropping from 6 minutes to 66 seconds saves developer time on every single run. Ten developers running tests five times a day, the math is straightforward.

The problem is that most engineering work lacks that kind of before/after measurement. Not because it is unmeasurable, but because nobody set up the baseline. Profile before you optimize and the return on investment calculates itself.

In such a clear-cut example, I think we have saved the two hours.