Microsoft is taking a more aggressive approach to keeping your PC updated - it's taking you out of the equation.
Here are the highlights:
- Updates will be applied automatically.
- If you have more than one Win10 PC on your network, only one will download the updates and any others will get those updates from that machine, saving your bandwidth.
- Windows Update has been removed from the old Control Panel and moved into the Settings app, under "Update & Security".
- Updating is now all or nothing - this is the aggressive part. The only option you will have deferring any necessary reboots (in Settings). The exception is Win10 Pro which can defer upgrades.
- You can uninstall an update after it's been installed in Control Panel...Programs & Features...Installed Updates (left margin)
- Windows won't download updates on metered connections. If you sometimes use your phone as a hotspot, you can (and should) mark that network as "metered", otherwise you might find Windows downloading updates on it. (Settings..Wifi)
- Improving on Win8's Refresh/Reset feature, Win10 will not have to re-update itself afterwards. Either of these will result in your 'fresh' PC being just as updated as it was before, saving hours of update time.