I look at it this way: Let's say I have task A and task B. If I multi-task both A and B for two hours, I will get much less benefit than if I do A for one hour, then B for another hour. Also, if you are doing any task which requires a lot of concentration, forget about mulit-tasking. Most people that say they can mult-task really can't - they just think they can. There are now quite a number of people dead or injured because some idiot thought that he or she could multi-task while driving and tried texting someone.

I personally consider it a bad habit. The more split your attention is, the worse you are doing what you are doing. When you focus your attention, you are fully present with what you are doing and you are fully aware of what is happening in front of you. I also think that anyone CAN multi-task, but it's a choice. People who are perfectionistic and meticulous (like I am, for example) avoid multi-tasking, because it reduces the quality of all of the tasks you are doing. However, society at large considers multi-tasking to be something desirable.

Multi-tasking the ablity to do several different things at once. Example: I can talk on the phone, fold clothes, and do homework at the same time. This is called Multi-tasking. It is not " good or bad", it is more like an ability you have.