When things are "a pain to maintain," code gets worse and worse over time. Performance then suffers because no one understands what's going on. In other words,

When things are "a pain to maintain," code gets worse and worse over time. Performance then suffers because no one understands what's going on. In other words, I believe that in the long run, complexity is a far bigger performance risk than technical overhead like how long it takes to make a web request. It's much easier to optimize away those kinds of problems away than to make an awful codebase understandable. In practice, I see service architecture as a way of making people think harder about how different parts relate to each other.