I work both 8 & 12 hour night shifts also on a med surg & oncology unit. If I work 8 hours I am required to do one assessment, if I work 12 I am required to do two assessments. For the second assessment if nothing has changed there is the option to choose "assessment unchanged" for each area such as neuro, cardiac, etc. 4 hours shifts also have to do 1 assessment. The same rule applies for daylight shifts.