Over the years I have tried a variety of backup strategies, from two different Drobos, to using Time Machine (Mac backup that backs up all the time so even a file erased earlier today can be recovered), to various external drives.
Drobos were slow, and given they were backup, the fact that they back up redundantly was somewhat unneeded, and given they stay plugged in at home, don't solve the problem of a power surge or fire.
Time machine has proven handy in the past when something got corrupted and I needed to go back to before the corruption, but the cost in slowing down the computer has been unacceptable.
All methods have had their problems. Taking the time to find all the raw files to back up onto one hard drive is problematic, though easier since I started using Lightroom, but not for the old files.
Today I have started what I hope will be both easy and fairly strong insurance against failure.
I picked up a hard disk caddy, and am now doing a 1:1 backup of each and every hard drive that is used as primary storage for my images. No more shuffling files and storing multiple drives onto one backup. As long as the receiving drive is as big or bigger, no sweat. I plan to do two entire sets, one for home, one for the office. The home set will be backed up in the future on a regular basis, the office set probably no more than once a year. Both sets of hard disks will be sitting unused and unconnected and at low risk of loss.
So far the process is slow, so it's something I'll run overnight for each one.
I might still consider time machine the main few hard drives but not for all the peripheral ones (of which there are half a dozen, on top of the four in the desktop Mac Tower, and only if it doesn't get in the way.
Is this ideal backup - absolutely not - I could lose an image from the last few months in a catastrophic failure, but I have Lightroom set up to make duplicates of all images as I dump the memory cards, so the worst I'd lose would be an edited image of less than three months age - that's something I can live with, especially as often with my favourite images, they get saved multiple times during the editing process, and in conversion to TIFF for large scale printing, and with toning, etc.
The big thing is it's better than what I have at the moment, which has been piecemeal for the last couple of years due to a variety of technical glitches saving to raid machines.
So, simple, redundant, and doable, that's what I'm looking for.