I have a 1TB Seagate FreeAgent external hard drive which I purchased back in 2008 (or was it 2009?). It was my media box and archive for old work-related files, until I got a 2TB Western Digital external earlier this year. At this point, the Seagate is acting as my Time Machine backup, and until now, it has seen no issues whatsoever. However, soon it will be 3 or 4 years old. Should I look into replacing it, or just use it until it craps out on me?