Change Android Tablet Layout with a Launcher

Google Now on Google Play (image)

Every Tablet/Smartphone comes with a Launcher.
example : Tesco Hudl2 has the Hudl Launcher.
The Launcher is the 'look' of the layout (and some other things).  

Android Tablet/Smartphone :
You can change the default Launcher with many available on Google Play (Apps)

Popular Android Launchers (on Google Play) :
Google Now Launcher
Nova Launcher

A launcher may :
Speed up your device a bit.
Have a better look.
Be more intuitive.
Do away with any pre-installed bloatware.

Links :
Techradar : 10 best android launchers