Just like rewriting a code base is sometimes the best approach. However there is a significant risk off learning the hard way why things were done a certain way

Just like rewriting a code base is sometimes the best approach. However there is a significant risk off learning the hard way why things were done a certain way. There is a lot of experience embedded in old, running systems. If you don't understand it well enough to change it in place, you can do a lot of damage trying to replace it.