Following the KISS principle and making systems as simple as possible therefore easy and cheap to maintain and expand. Which can include, not necessarily using the latest most fashionable tech if it doesn't solve the Use Case better. In my many years of coding, I've found many otherwise highly intelligent capable people, seem to devote herculean mental effort to understanding unneccesarily complex systems and keeping many details in their heads that needn't be there if it was designed sensibly.