Why? When placing the components - second time, you will know which direction you have some free space.
Why? You see directly and clearly from your schematic how the pins can be used.
Why? Very often this is used during board assembly and it is very useful during debugging.
Why? Helps during assembly. Can prevent placement issues during PCB design (e.g. too close, wrong rotation,…)
Why? In most cases, they will not help you.
Why? For example, you may want GND/PWR separate CLK signal from the others, it helps minimize crosstalk between signals on a cable.
Why? Assembly house uses them.
Why? Helps you to identify symbols and footprints which you need to check, helps to speed up schematic drawing process
Why? When doing schematic and layout for weeks / months / years and moving your hand all the time, you really need a good mouse.
Why? It helps with power noise filtering, easy to measure currents, circuit can be disconnected, …
Why? In some cases you may want to use exactly the same components because of software / hardware compatibility.
Why? It melts at lower temperature and behaves better than un-leaded tin
Why? It helps you to find possible problems before mass production
Why? It helps you quickly jump to the right page
Why? It’s a simple way to check if everything fits correctly and if everything is in the right place.