Repetitive tasks can be tedious and boring. Repetitive tasks in aircraft maintenance engineering are typically performed several times during a shift, or a number of times during a short time period. An example of this would be checking life jackets on an aircraft during daily inspections. The main danger with repetitive tasks is that engineers may become so practiced at such tasks that they may cease to consult the maintenance manual, or to use job cards. Thus, if something in this task is changed, the engineer may not be aware of the change. Complacency is also a danger, whereby an engineer may skip steps or fail to give due attention to steps in a procedure, especially to check something which is rarely found to be wrong, damaged or out of tolerance. This applies particularly to visual inspection.