I had to deal with many sizable codebases of legacy code over the years and even answered a similar question once on StackExchange. Apparently people liked the

I had to deal with many sizable codebases of legacy code over the years and even answered a similar question once on StackExchange. Apparently people liked the answer: http://programmers.stackexchange.com/questions/155488/ive-inherited-200k-lines-of-spaghetti-code-what-now http://programmers.stackexchange.com/questions/155488/ive-in... The question was within a somewhat specific context (team of scientists, visual programming environment, etc...) but I use the same approach for all projects. Never reached 3M LoC for a single projet or system component though. More like 1.5M. Anyways, that process works for me. Maybe it does for others.