Five years is a decent span, considering the drive is working 24/7. You didn't mention which manufacturer's drive and model it was. You can always buy two WD RED drives and a cloning dock, and clone the current one to the other one, rotating them every 90 days (or whatever you like). I've been doing that with a pair of 4TB drives for a few years years now. The drives will last longer (twice as long, maybe), and additionally, you don't lose more than 90 days of recordings if one drive goes belly up.