With respect to all of these ideas I wish to comment in that how are you backing up? Is it a straight copy without verification? Possibly a bad move. After using several different backup programs I found that Paragon's Hard Disk Manager Suite was an excellent product based on the what the product offers, their client base and tenure in the business and cost is a mere $50. There are other tools in the suite as well for partitioning, etc. You should be doing a data verification at the very least if using a copy method. Without verification you've got no way of knowing whether the file(s) were copied properly for a variety of reasons. Paragon will actually tell you if a drive is faulty as it checks the drive before backup. I do IT for a living and this actually happened at a client's. Ultimately I replaced her drive. In addition, I use Diskeeper. When files are created fragmentation takes place. In NTFS you have 4096 bytes in each cluster size. Each RAW or JPG or TIF (etc) can have numerous clusters which are tossed about the drive in no apparent order. When a file is called up to be read the drive spins (unless solid state) to assemble the file which creates heat, wear and tear, etc which all shorten the life of the drive. Solid state drives are not excluded from fragmentation of course. Diskeeper keeps your files defragged both in read and write mode and places your fave files and folders at the front of the drive (it does a lot more). It runs real time, small footprint and no performance impact. All HD drives on a single PC are kept at 0% fragmentation. You can run all kinds of reports on the drive. There are various indicators that will tell you the drives health as well. Images / Videos due to their size (IMHO) have the one of the biggest impacts on a drive's performance. I minimize my risks with both of these software tools and have yet to have an issue losing with my personal data or a client's. I've got a link to disk keeper on my site if anyone is interested drop me a note. I can get you a demo. PS they are now called Condusiv Technologies. Sorry if this sounded like an ad but its my personal experience and using these products daily. Been using Diskeeper for approx. 9 years and know it well. It's on every server I manage.
I've used diskeeper in the past, worked fine. Generally if it's a single large disk that you simply dump photos onto without deleting, chances are you won't get much, if any, fragmentation. Paragon seems like simply a quality backup solution, but there's nothing inherently unique about it. Doing basic S.M.A.R.T. checks, there are a bunch of tools out there, and you can always use something like rsync and/or par2 parity blocks and checks which are F/OSS. However, Paragon is likely to do all that in a much easier to use, nicer to use, prettier package that will probably be well worth the cost since it seems fairly inexpensive.
That said, data at rest on a HDD is, over time, likely to experience bit-rot, which is where a proper backup solution will include some form of parity generation which can at worst detect a problem, and most of the time actually fix/recover the missing data. This you get automatically with a filesystem such as ZFS, but not NTFS, Fat32, Ext2/3 (not sure about Ext4, I don't think so). You can generate that information from my previously mentioned par2 generated parity blocks, or I'm sure there are other tools out there. Not sure if Paragon would do that or not, something to look for in the feature list anyway.