I was negligent at preserving timestamps during previous backups, so the exact age is lost, but my oldest files are MS Works and Word Perfect documents from Windows 3.1 era in the early 90s. Aside from documents, I think the next oldest are mp3 files that I downloaded directly from the internet in '96 (pre-Napster days, back when you could just find websites that offered mp3 downloads directly). The quality is terrible due to aggressive compression so I should probably just delete most or all of them, but at this point they feel like artifacts. There's also a Weezer music video that came with Windows 98 (IIRC) that I still have.