It's so frustrating when you get ready to send holiday or birthday cards and realize you have no clue what your recipients' most recent addresses are. Try this: every time you get mail from someone, rip off the part of the envelope with the return address on it, and store in in a folder or envelope. Every year, go through the envelope and make sure the addresses are current. So much easier than writing (and re-writing) addresses in a book or on a spreadsheet all the time!