List hygiene means keeping an email list clean and active. This involves removing email addresses that never open messages or are no longer working. A clean list helps emails reach real people instead of dead inboxes, which improves delivery. It also saves money because sending emails to inactive users brings no value. When people only receive emails they care about, trust improves over time. Regular cleaning also helps understand who is truly interested. Many beginners ignore this step and face problems later. Do you think list cleaning should be done often or only once in a while?