One other thing.
Microsoft have never tried anything like this before, to upgrade Windows on millions of computers all over the world at pretty much the same time.
So there is a possibility it will all go pear shaped.
So if I were you I would not rush to install it on July 29th or a date near that.
I would leave it for a month or so, maybe longer, to let them iron out some of the major bugs.
I used to work in software development and ALL software ships with bugs, some more major than others, and it may turn out that this version of Windows 10 has some hidden bug or other that nobody has discovered yet.
Let others have the pain of it all going wrong, and stand back and install Windows 10 at some later date like September.
Windows 10 is free for a year so you have plenty of time.