I have a 2010 macbook pro with snowleopard 10.6.8, & have been using it with an apple cinema monitor, with displays set to mirror mode. i read about using clamshell mode, & a concern I have is that when I come to power on my laptop, I will be opeing the lid again to get to the power button. is there real benefits to clamshell mode besides saving a little space? do I preserve the laptop monitor with it being turned off while using with an external monitor? I ask because of a couple of concerns, one is heat issues with lid closed, the other is lid hinge wear. Will the lid hinge wear out after closing it to activate clamshell mode, & opening it up to power on each day? I also read an article saying that one can turn off the laptop monitor with out using clamshell by making the external monitor the primary display, & then dimming the laptop monitor all the way down. It is a little tricky using an external monitor with the laptop & turning off the laptop monitor, as opposed to just using both monitors in mirror mode. I do want my laptop to last as long as possible, it was expensive, & it would be nice if lasted more than 3-5 years. So is it critical that I use clamshell mode?