[kat]

My employer started using microservice as a way to update technology. We didnt have time to rewrite the main app, but new features were written in microservices, and those services used new technology. The savings wasn't a number, it was quantified as pass/fail.

We needed to update tls and other security areas, customers would have sued us and/or left us otherwise. This was made possible by refactoring into microservices. We also did it for quicker deployments, again customers were seeing our competitors update a website with no down time, so if we didn't switch to microservices to increase our deploy time, we would have failed and lost customers. (This is a > 10 year code base for B2B enterprise software, so don't judge us too harshly on these short comings)

Quantified savings is a hard and confusing thing to track from a tech perspective, but a sales person stating how many licenses you're going to loose if you don't do x is pretty easy to track!