It would be nice that ticket availability could be linked with dates, so for example certain ticket would available only until certain date. This could help with early bird tickets which are offered at a discounted amount but only available until certain date. When that date is reached, that ticket would become unavailable automatically.
This would be in addition to ticket availability based on quantity. So whatever condition is reached first make that ticket type unavailable, either the ticket amount is up or the date is up.