It seems like the only distinction between an "IDE" and a "Text Editor" nowadays is that an "IDE" is slow to start up but a "Text Editor" is fast to start up.
Everything else that would be in an IDE historically (project browsers, intellisense, code completion, refactoring, integrated build and debugger UI, test runners, etc, etc) all show up in "Text Editors". The only question is how good that functionality is, which varies between editor-language pairs.
In my mind the biggest difference is that in an IDE I need a stateful "project" or "solution" and with a text editor I don't.
Visual Studio is very much an IDE, but it is perfectly capable of editing a single file too. I think the only reason people tend to use something else for single files is because it tends to be slow to start up.
If you do mostly consulting work, small projects, switching between languages with poor IDE support (usually dynamic languages), you'll probably use a smart editor. You'll launch that editor multiple times per day, close it, reopen it, etc.
We should talk more about workflows, there are a ton of them and they're very different in my experience.