Intervals doesn’t do accruals but if you need to track total time it can definitely do that. Vacation and sick leave can be tracked in Intervals by utilizing a “Time Off” project. Unless you need modules we recommend creating one “general” module for this project. That way, when time is added and the project is selected the module is automatically selected. Work types of vacation and sick leave can be associated with the project to track the type of time off.
For reporting, the crosschart can be helpful for reporting on this project with people and work type for the axis.
Here is an example of the Crosschart
For communicating when someone is off, the home page can be used with public notes to show when someone is unavailable. Here is an example.