Size of icons on the Home screen depends upon the choice of the user. Some users like smaller icons with minimum number of icons on the Home screen and like more and more vacant space on the Home Screen. While, on the other hand, many other users like large number of icons and yet bigger ones on Home Screen. Likeness of size of icons on Home screen also depends upon the eyesight of a person which changes in proportionate to the age of the person. So, one can say that aged persons like icons with bigger size.
Understanding the difference of age and eyesight level between users, Android has included a feature in the KitKat 4.4.4 to show bigger icons if liked by the users.
You may also use bigger or smaller icons on the Home screen of your Android device but if you need, I suggest you to see instructions.
Instructions
1: Tap anywhere in the bottom half of the Home screen of your Android 4.4.4 KitKat device to open up ‘Open / Close Menu’. Alternatively, you may tap the pre-configured Android button to open ‘Open / Close Menu’. 
2: Tap and drag the shadowed part of Home screen upward to expose the HOME SCREEN SETTINGS screen.
3: See; the status of ‘Larger Icons’ on the HOME SCREEN SETTINGS screen is ‘OFF’, i.e. currently, smaller icons are being displayed on the Home screen.
4: Back on the Home screen – see the smaller icons are displayed on Home screen.
5: If you want to show larger icons on the Home screen, just tap the ‘Larger Icons’ on the HOME SETTINGS SCREEN, and its status will be changed to ‘ON’.
6: See; now the icons on the Home screen are shown a bit larger. 
That’s All!