Specific battery support time different models vary widely, generally in about two hours, of course, some 5 to 10 hours of model, which is generally the same computer's power consumption and battery capacity are related. 
Plugged in the power play is not often the battery is not good? The question everyone has been great controversy, actually scored the battery is to reduce battery work, but as long as the battery is now charged, and not at work, such as removing the battery, in case of sudden power loss, the problem is big, because the machine there is no battery, 
 
The actual effect of removing the battery for battery maintenance is limited. 
And any laptop batteries are chemical batteries are of working age, the longer the time to put the worse the performance.