[spronkey]

Depending on how heavily coupled the legacy codebase is, "Simple refactoring" really may not cut it.

I mean, you can write a bunch of pinning tests, then try to prise out various bits and pieces, sure.

But what if all the stuff you're trying to prise out can now be accomplished with a few open source libraries that didn't exist way back, with a very simple rewrite of your business logic on the top?

That's a situation I've encountered quite a few times - a lot of legacy code that's largely boilerplate, with business logic drizzled over the lot, oozing into the little cracks.