[markvdb]

> I'm not saying you can't do the math, but as I see it, every factor adds in such a huge margin of error into both the numerator and the denominator that the result of the computation easily becomes pretty useless.

You just described TCO, unpredictability in TCO, capital intensivity and several kinds of risk. All super useful heuristics to guide a decison. Just don't try to squeeze them into one filter...

Take us deciding on buying a car versus car sharing. We wanted low TCO, low cash flow risk, and low environmental impact. The signal from the low TCO filter was slightly ambiguous, but both other filters were super clear. Car sharing it was.