I guess I’m left with some confusion. It sounds like most people are saying that closing the lid should put it into sleep mode and that’s that. But if I close my lid things remain on the external monitor. One person wrote that since I was in clamshell mode (no idea how I got there) then everything moved to the external monitor and when I opened the lid everything moved to the internal display (thus I used Display Maid to restore). I guess that makes the most sense, though I’m not sure how I ended up using clamshell mode.
I guess one question I have is - if I’m not using an external keyboard is there any reason to not close the lid at night, or when I go out, and let the MBP go to sleep. Just to keep it from getting dusty? Are there any drawbacks from letting it go to sleep when not using it?