The online text talks a little more about non-value added activities. The text asks three questions to determine if an activity adds value:

Is the activity necessary?

Is the activity efficiently performed?

Is the activity sometimes value added and sometimes non value added?

It is amazing to think that we might perform activities that are really not necessary. Many of us might perform a task because that is the way the job has always been done. If you are not sure if something is really used by someone, it is a good idea to ask them if they still use it.