To design professional UI (User Interface Design) is not about just creative designer and design ideas. Designers design the UI for particular products without knowing some basic principles behind it.
While creative User Interface, you have to face 2 interrelated limitations:
1. The limited amount of information that can be conveyed through a single screen.
2. The limited amount of information that a user can process at one time.
The benefits and costs compromises can cut all the levels of UI development in each aspect like navigation design, font size and other aspects too. I have come across some of the important benefits and costs of design decisions below:
Shallow information architecture
Benefit : Fewer clicks to find info
Cost : More clutter
Deep information architecture
Benefit : Clean, reduced clutter
Cost : More clicks to find info
Small font
Benefit : More information per screen
Cost : More difficult to read for some users
Large font
Benefit : Easier to read
Cost : Less information per screen
Drop-down box
Benefit : Selection amongst many choices using limited space
Cost : Hidden choices
Radio buttons
Benefit : See all selections at all times
Cost : Additional space required, clutter
Icons
Benefit : Quick recognition once learned, aesthetically pleasing
Cost : Must be learned
Text links
Benefit : Always understood
Cost : Must be read, do not stand out as actionable items as much from other text
Abbreviations
Benefit : Save space
Cost : Must learn or recognize
Full text
Benefit : Easily understood
Cost : Requires additional space
Keyboard shortcuts
Benefit : High speed of data entry
Cost : Must be learned
Point and click
Benefit : Intuitive
Cost : Additional time required for interaction due to increase motor skills required