How often do you send broadcast email?

The question has come up about how often to send a broadcast email. It has been my experience that twice a month seems optimal. If you have an event coming up and send email every week just prior, that’s ok. But, someone wanted to send an email a couple times a week. It wasn’t a religious message or self-help issue. It was to sell inventory. My feelings are that if you send me a lot of ads you’d better be entertaining. If not, I’m deleting them.