Member and donor segments build themselves from your membership records and giving history, then keep sorting fans into groups like lapsed and first-time donors as new activity comes in. There is no list to build by hand and no spreadsheet to maintain before a renewal push or a giving campaign.
For venues running membership programs or fundraising alongside ticketing, knowing who is about to lapse or who just gave for the first time is the difference between a timely ask and a missed one. Because these segments update from every purchase, gift, and click, the list your team works from is always the list as it stands today.