I just finished the W10 update.
I checked the flag notification at 6:25 PM and it said is was ready.
I clicked OK.
At 8:00 PM I told it to use the defaults, as they can be changed later.
At 8:10 all was done.
Same background and all setting the same as in W7. Just as I left them.
This was on an older Acer with W7 and 4 gb ram.
I expect the wife's laptop to go quicker as it is W8 with 8 gb ram.
Even my older Office 97 programs work and they all seem faster opening.
I did not have to do anything.