How do you re-engage past applicants without annoying them?

Three things, and none of them is the fact of being contacted. The first is irrelevance: a message about a role nobody in that segment could do reads as a mailing list rather than a conversation, and it teaches the reader to skim the next one. The second is anonymity, because a message from a no-reply address asks for interest while making interest impossible to express. The third is amnesia — writing to somebody as though you have never met when they sat through interviews with your team last year is the version people describe most bitterly afterwards. Each is a content failure rather than a frequency failure, which is why sending less rarely fixes a campaign that is landing badly.

The segment decides the message, so choosing it first is what stops the message becoming generic. Useful cuts are the ones that predict fit and timing together: role family, seniority, location, how far they got with you last time, and how long ago that was. Somebody who withdrew at the offer stage needs a different note from somebody who was screened out at application, and a specialist who left the process for a competing offer needs a different note again. A candidate relationship record is only worth keeping if it carries enough of that history to segment on, which is the practical test of whether your pool is a pool or a list of names.

Reference the specific thing that connects you: the role they applied for, the stage they reached, or the team they met. Say what has changed and why you are writing now, because a message with no occasion reads as automation. Say what you are asking for and make it small — a conversation, not an application form. Name the person writing and make a reply reach them. And be honest about where they stand: if the answer is that you would like them to apply again through the usual process, say that rather than implying a shortcut that does not exist. People forgive a modest ask far more readily than an overstated one.

There is no universal number, and any figure quoted as one should be treated with suspicion, because tolerance varies enormously by seniority, by how the relationship started and by how relevant the last message was. What is more reliable is a rule that the cadence is agreed rather than assumed: tell people at capture what they can expect to hear from you and how often, then send at that rate rather than at the rate the hiring calendar produces. The practical discipline is to look at what a single person received over the last year rather than at campaign volume, since an individual sitting in four segments experiences four times the frequency anybody planned.

Immediately, completely and without a retention flow. A person who opts out of hearing about future roles has given you clear information, and the only thing worth doing with it is honouring it across every segment and every channel rather than the one campaign they replied to. The commoner and more damaging failure is partial removal, where somebody is taken off one list and reappears from another six weeks later, which reads as bad faith rather than a system limitation. Where you have a lawful basis question about holding the record at all, that is a different decision from the marketing preference and should be settled with your own legal advice rather than inferred from an unsubscribe.

Replies rather than opens, and hires from the pool rather than replies. Open rates tell you the subject line worked and very little else. The measures worth watching are how many people respond in a way that starts a conversation, how many of those enter a live process, and what share of your hires in a period came from people you already knew. The counterweight measure matters just as much: track opt-outs per campaign, because a sequence that produces a few conversations while quietly burning down the pool is losing you the asset it was meant to build.