I have a 6-drive Netgear ReadyNAS Probusiness that is currently at about 3TB. It supports Time Machine, so I backup my 2 Mac Laptops through Time Machine only. I backup my desktops and all my other files on the ReadyNAS. I have UPS on all my desktops and ReadyNAS to prevent any power outages from causing data corruption. This came in handy a few months ago when a tree branch fell and took out my power lines.<p>I have two 2TB drives that I switch between every couple of months that I backup my ReadyNAS to. Because this data is basically my entire digital life (my photos, documents going back to about 1993, emails, etc), I don't trust a straight file copy, so I wrote my own simple bit-by-bit file comparison program. An engineer at NetApp told me all the horror stories that he's been involved with in terms of hard drive reliability, including things like the hard drive reporting to the OS that it wrote everything correctly, when it fact it didn't, so I've become pretty paranoid. The last thing I want is to make a backup, and then find that what was written on my backup hard drive was corrupt.<p>I have a couple of 500GB hard drives that contain some older archived data from 3+ years ago, so my older photos and documents have about 4 different copies. The only thing I don't implement, which is probably my biggest weakness, is that I don't store any copies offsite, so if there's a fire, I'm screwed.<p>Except for database and photos, my data growth has slowed down considerably. I would guess that my database data grows about 100 GB every year (I collect stock quotes every day), and my photos and videos are, on average, 10-20GB. This year was an anomaly because I went on a road trip where I used 2 GoPros to take time lapse photos and videos of the entire road trip, and that data itself is about 100 GB, and 99% of it is useless (and embarrassing).