Just learned that my external hard drive which held my pics is unrecoverable. Unfortunately I did not have all of them backed up some where else. Hard lesson to learn and am looking into the best and least expensive way to have multiple back ups.
It happens to everyone at least once... There are a lot of suggestions in this thread already, but I will add my process to the list...
I have 2 internal hard drives, C and E (data). Every day, my backup program (SyncBack Pro) copies the contents of E to a spare partition set up on the C drive, and the contents of C to a spare partition set up on the E drive. Then there is a profile running automatically which takes the contents of both to an external drive. Every month or so, I run a manual backup to a second external drive which is not plugged in until I am doing this. Just to guard against power surges, and that sort of thing. I also have everything backed up to the cloud using Carbonite. This is a last-ditch precaution, since it would take a *long* time to download everything from them, but it is nice to know it is there if needed. I consider it well worth the $50 or so per year for the extra insurance.
This system has saved my bacon through several hard drive failures, and I have never needed to pull stuff back from the cloud. Yet. One of these days I will get a couple of spare drives, and keep a copy of my stuff at a friend's house, or even in the car. I haven't done this yet, on the basis that if we have a catastrophe which destroys my apartment, saving old photographs will be somewhere well down my priority list!
I also have an external Blu-ray drive, and have thought about burning copies with that, but my pictures folder is almost 700 GB, so it would take something like 20 disks to hold it, and I haven't had the patience...
Given that I already had the 2 large internal drives, I reckon my total outlay has been maybe $200 for the externals, plus $50 per year for Carbonite. You can pick up 4 or 5 TB drives for not much over $100 if you look around. I agree with the sentiments about Seagate, too. A few years ago they *were* the drive to go for, but I have heard many tales of woe in recent years. One of my externals is a Seagate (the older one), but my new 6TB one is a WD.
Only you can decide your comfort level of safety vs. cost, but I hope this setup shows that you don't need to spend a fortune for peace of mind.