Sent out three or four times a year currently. You can unsubscribe at anytime. Except on weekends. Weekends are for resting. No unsubscribing on weekends please.
Technically you can unsubscribe on weekends since it's all handled automagically by a web robot or some sort of magic. But magic is dangerous so you should probably only attempt it Monday to Friday, 9am to 5pm, right?