I started at 11:30 A.M. Ran the Sierra install. After that, I ran all the App Store updates for OS X 10.12.2 and for my software (Pages, iMovie, Xcode, etc.). All done at 1:45 P.M.
What used to take several hours now took two and a quarter. I guess Apple is doing something right. Or maybe it's because my MacBook Pro now uses SSD instead of the old spinny hard drive.
Next year, Apple will be changing the hard drive formatting of Mac hard drives to improve SSD performance. I will see how that goes.
P.S. Last night, I made bootable Mac OS X El Capitan backups to two external hard drives. I ain't dumb!