For extremely large projects, an activity may be made up of several smaller subactivities. Each activity might be viewed as a smaller project or a subproject of the original project. The person in charge of the activity might wish to create a PERT/CPM chart for managing this subproject. Many software packages have the ability to include several levels of subprojects.

Major events in a project are often referred to as milestones. These are often reflected in Gantt charts and PERT charts to highlight the importance of reaching these events.

In addition to managing the time and costs involved in a project, a manager must be concerned with the resources used in a project. These resources might be equipment or people. In planning a project (and often as part of the work breakdown structure), a manager must identify which resources are needed with each activity. For example, in a construction project there may be several activities requiring the use of heavy equipment such as a crane. If the construction company has only one such crane, then conflicts will occur if two activities requiring the use of this crane are scheduled for the same day. To alleviate problems such as this, resource leveling is employed. This means that one or more activities are moved from the earliest start time to another time (no later than the latest start time) so that the resource utilization is more evenly distributed over time. If the resources are construction crews, this is very beneficial in that the crews are kept busy and overtime is minimized.

There are numerous project management software packages on the market for both mainframe computers and personal computers. Some are hosted locally, while others are cloud-based. Some of them include Microsoft Project, Clarizen (cloud-based), OmniPlan, and OpenProj. They can be used to develop budget schedules, automatically adjust future start times based on the actual start times for prior activities, and level the resource utilization.

Good software for personal computers ranges in price from a few hundred dollars to several thousand dollars. Companies have paid several hundred thousand dollars for project management software and support because it helps management make better decisions and keep track of things that would otherwise be unmanageable.