You have no idea how unpredictable it can be.......Once you file the I-485, you are in a limbo period.....Once your I-94 expires, you are out of status......theoretically, once you file the I-485, you are in "authorized stay" until the I-485 is either approved or denied....but that is not a legal status....it is a policy,.....Be prepared for the inability to work, travel outside the US for months.