Is it a bad idea to keep a Macbook pro always on? [duplicate]

Possible Duplicate:
Is it better to use laptop on battery or on AC power?

I never turn off a macbook pro I've at home. It's always connected with the power source, but with the lid closed.

Is there a problem? Is the battery going to die slowly because of this?

If you can, try to run the battery down every now and again. From Apple:

Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month.

This debate very often pops up here. Long story short: Make sure you unplug it every once in a while (maybe weekly) and let it drain and charge. It is important to cycle the battery every once in a while for both the health and calibration of the battery. Check Apple's site for very specific Macbook battery tips here.

For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing.

There are heat concerns - with the lid closed, there is less space for the heat to circulate. The hotter many computer parts are, the more likely they will have a shortened lifespan.