Macropod, I have worked with your code:
MsgBox Format(ActiveDocument.BuiltInDocumentProperties("T otal Editing Time") / 1440, "[d] hh:mm")

It gives about the same number of minutes and seconds.
It seems to start as soon as you open a new document. The clock starts ticking as soon as you open a new document.
I am convinced it is accurate too.

However, with my work, I open a new document and may not start on a piece of work for several minutes or may an hour later. I am having so much fun with the ease of my work using macros and I marvel at the time savings; so I get everything ready to go ahead of time. Everything is set up before I start on a piece of work. I have to balance accuracy and speed, but the speed part is thrilling. Without Macros, one piece of work takes around 30 minutes of fast, intense work. With Macros my fastest time is 8 minutes and 19 seconds! Of course some of these pieces of work require telephone calls and other research to clarify the data; and this research may greatly increase the time.

And I have it rigged so that when I get a piece of work and start to work on it, the very first thing that happens is that I copy and paste an identifying Number using a macro that also grabs the Now time That's when the time starts.

Nevertheless, if I didn't already have the other code with lots of logic and code already set up I know I would use your code.

I have never studied Microsoft Word very much, I learned enough just to be able to write a document with some shapes and arrows. So I am surprised that anything exists such as your (ActiveDocument.BuiltInDocumentProperties("Total Editing Time") / 1440, "[d] hh:mm")

But I did recently buy a good book "Word 2016 IN DEPTH" by Faithe Wempen, a QUE Book. I bought it to compliment my studies of VBA. On page 39-43 Document Properties are discussed, including the Statistics Tab.

This is all very interesting. I must look this over to see if I might ever want to use anymore of these.