Those who know me know I'm a huge advocate of centralized data management systems. By that I mean a database that houses essentially all of your data (e.g., membership, events registration, all financial information, product sales, etc.).
One of the many reasons I like centralized data systems is that when the question "Where is that data?" is asked, the answer is always the same: "It's in the database."
All of us have experienced at some point a situation where data is needed, but the person who "owns" that data is not around, and therefore the data is inaccessible. ("Oh, Sally keeps that data in a spreadsheet on her computer. Unfortunately, she's out of the office today.") This is what happens when data is decentralized, or in silos. It becomes more difficult, and therefore more expensive (both time and money), to pull and analyze the data when we need it.
So look around your organization. When someone asks "Where is that data?" do you have an answer? And is the answer always "It's in the database."?