Door contact sensor

I have just installed a door contact sensor in my main entry point to my house what I would like to know is if I set the 60s exit mode in home mode can I leave the house then close the door without disabling the alarm each time I go to work? If this is true would it not be possible for someone to get into my house close the door and also not trip the alarm? For this reason do you all set entry and exit mode in home mode to zero seconds ? Sorry for all the questions and thanks in advance. Marc