[rmbyrro]

In my previous experiences, it really boils down to the unit economics.

If a given process generates $1 in revenue over a year, and it takes pennies for AWS services, that's a good sign your design is not going to break the company's pockets down the road.

In some cases, it's not easy to narrow the unit economics so much, which adds uncertainty to your premises, and there might be market fluctuations that change the unit economics in the future. I try to anticipate which areas are most likely to change and think of a trade-off in terms of short term speed and flexibility to change later, if needed. Almost always they're a trade off.