Telephone Timesheets supports one-time and recurring schedules. Recurring schedules can be recurring weekly schedules, or they can be any recurring pattern such as, monthly, yearly, the first Monday in September, etc. Telephone Timesheets uses standards-based calendar rules, so integration with third-party calendars can be accomplished.
Contact support if you are interested in a third-party calendar integration (e.g. When To Work, or When I Work)
Schedule entries are not required; however, a schedule is useful for things like enforcing timely clock ins/outs by using the call/text/email notifications feature of the system.
Also, if schedules are maintained in Telephone Timesheets either by manually entering them, or by synchronizing schedules from a third-party system, then those schedules can be exposed to employees.