couple questions about my macbook ?

please sorry for the noob questions this is my first mac . i usually use my macbook pro as a desk top so my question is. is it ok and is it safe to leave the macbook pro on sleep mode all the time?or should i shut down every night? and is it completely safe to leave it hooked up to the charger all the time?i now that at least 1 a week let it run on battery.i also have second monitor hooked up to my macbook pro with the vga adapter now my question is .would it be fine to all ways leave the vga adapter hooked up to the macbook pro?thanks for in advance .

Yes to all of these. It's highly unusual to turn off a Macintosh. They just don't need to be shut down. Just make sure that the computer and the power brick have sufficient ventilation and don't get too hot. Heat, not "being left on" is the number one enemy of your portable computer.