Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
It is totally up to you, some people will us it at the same time that they use their mouse others will use it for certain tasks/programs and use the trackpad for everything else and still others (like me) will abandon their mouse completely and use only the trackpad.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.