Important code needs love, it needs to be improved, made more robust, have security issues handled, consolidated if it starts to bloat, to be cleaned and kept l

Important code needs love, it needs to be improved, made more robust, have security issues handled, consolidated if it starts to bloat, to be cleaned and kept legible even for whitespace so you or the next guy can easily see and continue to look after all the moving parts. If it's important, it needs and deserves all those things; they are not "churn" but maintenance.