Sending permanence is the process of establishing a consistent sending volume and strategy in order to maintain ISP reputation. Here are some reasons why sender permanence is important:
Spammers will typically “IP address hop,” meaning that they’ll constantly shift traffic across many IP addresses to avoid reputation issues.
Consistency is key to prove to ISPs that the sender is reputable and not attempting to by-pass any reputation issues that are a result of poor sending practices.
Maintaining these consistent strategies over a long period of time is required before some ISPs will even consider the sender reputable at all.