generally you should always go to the manufacturers website for the latest drivers, but outside of the GPU its probably not too important unless you have an issue.
I never knew that the drivers were on my PCS home page, but all the dates of the drivers seem to be quite old mostly around 03/02/2014 however I did notice that the bios driver has a date on it of 13/05/2015 and that is definitely not what is actually the one on my laptop at present, however PCS has a cautionary note saying DO NOT UPDATE THE BIOS UNLESS YOU HAVE BEEN REQUESTED TO DO SO BY THE SUPPORT TEAM]
[WARRANTY VOID FOR INCORRECT USE]
So I would assume that it is not required to be updated on my laptop.
But it is an interesting question
Slightly off topic: Windows 10 drivers are pretty comprehensive for my old Optimus IV, you shouldn't even need to worry about finding and installing drivers for it. But yeah I know, it's not out yet. XD