Primary requirement of a CAD mouse

The least a computer mouse for CAD can have is

• scroll wheel
• left click
• right click

If you are a newbie wanting to get serious with Computer Aided Design, one of the first thing you should know is, you will not be able to use any CAD software without a computer mouse. 

I say that because, a couple of months ago, I have a friend who was trying to learn the basics in AutoCAD and he showed up at my door with a laptop thinking the track-pad was enough to start designing in AutoCAD.