Even with that most big providers (looking at Outlook) still use IP reputation. Some popular email blacklist providers will list entire /24s if they receive eno

Even with that most big providers (looking at Outlook) still use IP reputation. Some popular email blacklist providers will list entire /24s if they receive enough abuse complaints so you generally need a high quality provider that takes abuse seriously to prevent getting caught up with a bad neighbor or your own IP block. After using the same Digital Ocean IP for 8 years, I got unlucky and their /24 block got listed on spamhaus (or mailcop, or similar) and major providers (Outlook and Gmail) stopped accepting messages from my server. It works great until it doesn't