A lot of it happens in the backgound. It is at least a 15-30 minute process from start to finish. Very annoying if you have an older computer as it is sucks up a lot of resources updating during the background updates.
I normally don’t ever shutdown or restart my desktop. I like leaving program and stuff running so I can continue what I am doing when I get back. With an update I have to close out all of my shit and then shutdown and open everything back up.
I also swear when you have updates pending on a restart the computer doesn’t run very well.