I can't speak for the gp, but they were talking about inheriting a project/legacy code.
If I end up needing to go through legacy code, and there are a lot of gnarly, long methods/blocks, I'll usually add comments and regions to it as I go along. I'll use comments if I just want to note something, and a region if I want to note something about a region of code. It's my rough map. Being able to tell Visual Studio to arbitrarily collapse an area is handy for sketching it. The long term goal is to refactor, but it's handy as a way to quickly outline things.
If I end up needing to go through legacy code, and there are a lot of gnarly, long methods/blocks, I'll usually add comments and regions to it as I go along. I'll use comments if I just want to note something, and a region if I want to note something about a region of code. It's my rough map. Being able to tell Visual Studio to arbitrarily collapse an area is handy for sketching it. The long term goal is to refactor, but it's handy as a way to quickly outline things.