For a couple of years now I have been updating the drivers for my 2 GTX 680s by first wiping all traces of the previous version from my system (Windows uninstall > manual folder deletion > driver sweeper > registry cleaner), rebooting into the default windows VGA driver, and then installing the latest version. Is this arduous process really necessary as some have claimed? Or can I save time by just installing the latest version over top of the previous?
If you have the time a complete uninstall the install like you have been doing can reduce the chance of an error.
However usually just using something like geforce experience and updating it through that will do it fine.
it used to be the case you had to do that when xp was the o.s. of choice but since vista you can if you want just install a new set of drivers and they will take preference over the old. they did this to allow the user to roll back to an earlier working driver if the new 1 didnt install fully.
so yeah you can just install the new without removing the old and the system should be fine with it.
but if you start getting compatibility or stability issues you will have to remove them, clean the registry and reboot.
unlseast I am upgrading my GPU or have some problems with a particullar driver version I never go through the whole process you are describing. I don't remember having any issues caused by only downloading and installing the latest drivers.