I’ve never understood the cost/benefit of Carbonite. For $70 I can buy a portable 500 gb HD and use it to back-up my computer. I don’t leave it plugged in but keep it in my fire-proof box.
Because I work with critical files every day. One lost file could easily be several thousand dollars worth of labor for me.
I don’t have to worry about forgetting to back them up. Its done for me and is one less thing to worry about.
BTW, your fire proof box probably isn’t going to protect your hard drive in case of a fire. The heat will melt the drive even if the fire doesn’t.