Someone recently asked when they should purge addresses to remove spamtraps. To my mind this is actually the wrong question. Purging addresses that don’t engage is rarely about spamtraps, it’s about your overall communication processes.
Well maintained traps will actively bounce mail for 6 – 12 months before turning the address into a trap. In those cases it’s mostly the whole domain being turned into a trap, not just a single address. The common case where folks start hitting the recycled traps is that they have, for some reason, not regularly sent email to an address.
My general rule is if you’re actively bounce handling your mailings and you’re not avoiding mailing for more than a year then you shouldn’t have to worry about addresses turning into traps.
But you don’t just want to worry about spamtraps. You also want to be concerned about your overall reputation. For instance, an email address that never opens might have been abandoned by its owner (they forgot the password, moved to another account, whatever) and their failure to log into the address and your continuing to send mail to it turns it into a signal for the machine learning filters.
Alternatively, an email address that isn’t opening mail may never see the mail because it’s being delivered to spam and they don’t care enough to correct that. Every email delivered to the spam folder hurts your reputation, it’s less of a negative than if the user put the message there, but it still affects your reputation. Removing addresses that don’t engage removes negative hits to your reputation.
In both of those cases I tend to go reasonably long periods of time 12 – 24 months. But, there are arguments for longer or shorter, depending on your specific business model.
There are many good reasons to stop emailing addresses that don’t engage. Few of those reasons are specific to spamtraps.