The sweet spot for emailing your subscribers is different in every industry. You'll want to ask yourself what kind of business you are running, who the audience will be (are they just customers or do other people besides buyers matter?), when big events like sales happen regularly and consistently throughout each month/year period- all these things play a role when deciding how often should i send emails? Some businesses find that once per week works well while others might prefer 3 -5 times monthly instead! The key here though seems largely consistent: make sure they know about upcoming events and activities going on in your business.