I think gathering good data is very important. Knowing giving behavior can help you to determine when to make your next ask and how to determine a donor's prospective giving in the future. Some key data I like to look at is amount of first gift, campaigns that the donor has supported, amount of most recent gift, donor's giving potential (generated using donor's job history, address, etc.), and for donors who have lapsed, anecdotal data would be helpful to understand why.