A follow-up sequence is a deliberate series of messages sent after an initial outreach email, spaced over days or weeks, each adding something new rather than simply repeating the first. A typical sequence is the initial email plus two or three follow-ups over roughly two-and-a-half weeks.
Follow-ups matter because most cold emails are missed or buried, not rejected — silence usually means "not seen yet," not "no." Many practitioners find that a large share of their replies come from the second or third message. The final message in a sequence, the polite "breakup" email, is often one of the highest-performing touches of all.
The rule for a healthy sequence is that every message must add value — a relevant project, a useful question, a piece of company news — never just "checking in." A good sequence also stops the moment someone replies or asks you to stop.