Since Apple doesn’t even sell a Mac with that much disk space, you could back up five (or more) computers to that drive without running out of room. For traditional drives, prices are low, options are numerous, and capacities are so high that your only choices are “enough space,” “more than enough space,” and “way more than enough space.” I could point you towards a gigantic 5-Terabyte $139 Seagate USB 3.0 hard drive right now and end this article without another paragraph. I feel old saying this, but having used computers since before external hard drives existed, I can say with certainty that buying a hard drive is easier today than it’s ever been before.
