Ability to have multiple calendars
For example, allow us to have separate calendars for weekdays-only, 7-day, expected rainy days. Then, we could apply a specific calendar to each task and its duration would apply the correct finish dates based on the start date & calendar selected.
This is absolutely necessary. Anyone who manages projects in a production environment also needs to be able to schedule work on the weekend and holidays. And due to tight time frames, we need to be able to plan to the hour.
C. Yi commented
Microsoft, please add this capability. In MS Project, there are project calendars, task calendars, and resource calendars. We need the ability to make certain days non-working and some weekend days working days -- for example, many IT projects cannot deploy newly developed software/hardware during normal business hours so deployments are only allowed during Sunday or weekends.