I have worked in computers for many years but have never taken apart a laptop. And I have friends who have built their own computers from spare parts but to my knowledge none of them have ever taken apart a laptop. It just isn't done.
Hmm, I do it all the time. But Webservant is right, it's like surgery. You usually need to be very careful removing the keyboard bezel and other plastic trim parts. There are guides on the web for taking apart laptops, but it is not for the faint of heart.
I replaced a fan on a Toshiba Satellite, a screen on a Sony Vaio, and I've even soldered in extra memory on a netbook because they didn't leave a slot for expansion. The first time I took a laptop apart, I was resigned to losing it, but it went back together with great care. It gets easier as you tackle different ones.