The following examples should give you a fair idea as to which scheduling mode works best for your projects & tasks.

Manual Scheduling: Manual scheduling is useful when you want to be able to manually enter start and finish dates, without causing those entries to recalculate other aspects of the schedule.

If you want to explicitly schedule tasks to start or end on weekends/holidays, manual scheduling is the option for you.
A date-bound task for which you want to assign multiple resources with different allocations.
Sometimes project schedules are very informal. They begin as simple lists of dates from e-mails or meetings with clients. Managers do not have complete information on these work items. For example, they may only be aware how long a task will take, but they do not know it can be started until they have approval. In such cases, the PM might just want to enter the dates agreed with the client. In such cases, manual scheduling of tasks is most efficient way of scheduling projects.

Automatic Scheduling: Project Managers also need a scheduling engine that automatically calculates dates when entering or changing task information.With automatic scheduling, you let Celoxis build a dynamic schedule that calculates realistic end dates.

In a development project, a client discussion to finalize the project details needs to be completed before the SRS can be prepared or the development team can start designing their use cases. The client meeting can be postponed or rescheduled based on availability. This causes the dependent tasks to be rescheduled. In such cases, the Manager cannot practically modify the project plan every time. The start date of the dependent tasks should be rescheduled automatically when the predecessor completes. Automatic scheduling takes this into picture and helps the Manager to set dependencies and constraints so that the required tasks adjust themselves as commitments shift.
For a typical construction project, where contracts, bids and permits are all dynamic in nature and delays are evident, it makes sense to let Celoxis build the project schedule based on the task durations, dependencies and constraints the Project Manager enters.
A specific project task needs a scarce expert resource, and it must be scheduled around the resource's availability. Auto scheduling is your best bet for such tasks.

Browser not supported