The right email frequency depends on audience expectations, buying cycle, content quality, industry, and engagement data. Sending too rarely can make subscribers forget why they joined; sending too often can increase unsubscribes and spam complaints. A good starting point is a consistent schedule that you can sustain with useful content, then adjust based on opens, clicks, conversions, unsubscribes, complaints, and revenue. Segmentation matters because active prospects, customers, and cold subscribers should not always receive the same frequency.
Example
A local service business might send a monthly newsletter, a short seasonal promotion, and automated follow-ups after form submissions, while an ecommerce brand may send more frequent product and cart recovery emails.