People mention that said rewrite needs to have some immediate benefits. I actually like rewrites where no obvious changes are visible. These are rewrites, where

People mention that said rewrite needs to have some immediate benefits. I actually like rewrites where no obvious changes are visible. These are rewrites, where one anticipates future problems and does this work preventively. Three projects come to mind. 1) Rewriting a set of internal libraries from Python 2 to 3, because it's better to do early on, before compatibility problems arise. 2) Rewriting an ancient cli tool written in C++ into Go (nobody here knows C++, some speak Go). It has worked for years untouched, but you never know. 3) Rewriting a Fortran modelling tool into Go, because while people know Fortran, it maintenance costs are annoying and adding functionality is difficult or impossible. In all cases, no functionality was gained or removed by the rewrite, but future pain was spared thanks to these endeavours.