No, it's not a good idea.
The
Washington Post reports that the typical lifespan of a lithium-ion battery is two to three years, whether it is used or not. Lithium ion batteries are the lightest weight, most powerful and lowest-maintenance batteries in existence, but they have a drawback — a limited lifespan. Again from the article in the
Washington Post: "Lithium ion batteries are particularly susceptible to aging; as soon as one leaves the manufacturing line, its countdown begins. A typical lifespan is two to three years, whether it is ever used or not . . ."
My thought on the matter is that you had just as well use your battery as is most convenient to you, because you aren't going to extend the life of it by very much.
With that in mind, Apple's recommendations for extending both the battery life and battery lifespan can be found here:
http://www.apple.com/batteries/notebooks.html
Besides not being effective at extending the battery's lifespan, running without a battery has the added disadvantage of not having backup in case the computer is accidentally unplugged or there is a power outage. Also, it leaves the internal contacts exposed to dirt, dust, debris, and damage. If Apple intended for you to run it without the battery, they would have provided a battery hatch cover.
Just my ideas on the matter, Eric.
