Like all drivers, you are never required to install them. You only need to install an updated driver if it addresses an issue that you would like to see fixed. If you are happy with how the current driver is operating, then you have the option of sticking with it.
I also need to mention that there are people that should not install this update. For example, people with laptops what have custom graphics drivers from their laptop vendors that enable special features - hot keys, etc. - of the laptop. If you replace a customized graphics driver with an Intel generic graphics driver package, you will lose these customizations and, in some rare cases, end up with an unstable system. This is why there is the checkbox that you have to check in order to install this update; you need to check with your system vendor to ensure that they have not customized the graphics driver before replacing it.
Now, in the case of this particular driver update, there are a number of issues that people have reported that it seems to address. I will certainly be installing it on my non-laptop systems. Of course, I believe that everyone should be installing every update as it is released. After all, it's lonely out here on the bleeding edge and I need company... ;^)
...S
