What rules exist for the start and end dates of a performance?

When creating a performance (occurrence), these rules apply:

• Start date is required — every performance must have a start date and time
• End date is optional — but recommended for multi-hour events
• End date must be after start date if provided
• No overlapping validation — you can schedule performances close together or even on the same day (e.g., a matinee and an evening show)
• Past dates are allowed for record-keeping, but customers cannot buy tickets for past performances

The date and time are shown to customers on the event page and printed on their e-tickets.