Lead time & lag time

Lead time lets the second task begin earlier than the dependency would otherwise allow. For example, a finish-to-start link with one week of lead lets content writing start a week before build finishes. Lag adds a wait: if concrete needs a week to cure before the next task, the link has a week of lag.

Waiting time still occupies the schedule even when nobody is actively working on the task. Include it so the chart shows when the next activity can actually begin.

When bars overlap, check whether the overlap is deliberate. If one task needs the other's completed output, a missing dependency may be allowing an impossible start date.