The best frequency for sending out email newsletters depends on several factors, including your audience's preferences, the type of content you're sharing, and your business goals. Generally, sending newsletters on a regular and consistent basis can help keep your subscribers engaged and prevent your emails from getting lost in their inboxes. However, be careful not to send too many emails, as this can lead to fatigue and unsubscribes. A good rule of thumb is to aim for 1-2 emails per week, and consider sending more or less frequently based on your specific circumstances and audience feedback.