Loose schedules are the ones that do not require a strict scan time range and order of scanning your checkpoints. These are useful in cases where you just want to make sure that the Guards have visited a site any time within a loose time range (e.g. within 24hours).

On the other hand, Strict schedules are the ones that require a strict time range or specific order of checkpoint scanning. These can be of use if you want your Guards to visit sites in a specific order.