I'm sure I'm just missing this, but how can I set a task to recur the first day of each quarter?
you can find the complete list of date formats supported by Todoist here: https://todoist.com/Help/timeInsert
Unfortunately, it's not directly possible to set up a quarterly recurring task, but you could use the following formula:
every 91 days starting 1. Jan 2012
as an alternative.
We will consider adding more complex recurrence syntax in the future, though. You're welcome to vote for this request in our Votebox: