Comment by cosmic_cheese

Maybe not “need” in the strictest sense, but there have been more times than I can count where digging up old mail has either made things much faster and easier or helped me answer a random question that popped into my head about something that happened ages ago.

Old SMS, iMessage, Telegram etc messages have been useful from time to time too for similar reasons.

Both can also serve as exceptional time capsules that provide windows into past “eras” of life. I occasionally kick myself for not having archived mail and messages from a couple of defunct email addresses and chat apps… without them there’s a hole spanning a few years where visibility is limited.