Waiting time to start an activity is called Lag OR Lead time, if Waiting time is +ve it is called LAG and if it is ve it is called LEAD TIME
As per general International standard it is not recommended to assign either Lag or Lead time, one of the reason is that it is not shown in the Gant chart and once these activities become on critical path it shows wrong impression for the project completion, as project delay can be reduced by eliminating the Lag/Lead time. There are following three methods to highlight Lag or Lead time
1) Show Successors and Predecessor Details columns in layout
2) Use Filter command
3) Use Report command
The 1st two are time consuming and less reliable whereas the last one is the most accurate and fasted method to get the desired results
For the second method we need to modify "USER PREFERENCE" and select "Shown Duration Label" so that it will shows "d" as unit of measurement of duration
In the 3rd method we can generate the report in Excel format to shown all the activities with lag or lead, it is fast and help us to analyze the schedule
As I mentioned above according to the international and general practice, use of lag/lead is not recommended instead we need to find a way to eliminate it, one of the method is to assign an activity instead of lag, because once we start updating the schedule it is required to reduce the amount of lag to estimate the real scenario of project.