We all know stereo sounds ‘better’, so why bother recording in anything else? As a general rule, unless you are recording through more than one microphone you are recording a mono track. This track can later be panned left or right to provide stereo output. A mono track panned to the center is identical to a stereo track with identical left and right channel output. If you want the thick sound of stereo, you can layer mono tracks. It’s possible to copy and layer a single take, but the results won’t be quite as good. The extra time to record multiple takes to layer will show in your final product.
Take a look at the full article here: http://thedawstudio.com/Tips/Mono_and_Stereo.html