Unfortunately such tools have just as great a likelihood of requiring a backup to recover from errors they make as not. Cache cleaning is one example. We get so many people come into these boards whose applications no longer launch, or unexpectedly quit. What is the cause? LaunchServices cache files have gone south. And guess what sent them there? Tools such as Onyx, Macaroni, Applejack.
The Mac OS does all the cache cleaning I have ever done on this computer.
I am sure that some people have over-zealously applied some of these tools unwisely, but most of the references I have seen to cache cleaning and deletion on these forums in the past year or so have been as solution recommendations (which sometimes work) to people who already have existing computer problems rather than being caused by them toying with their computers. Again, my main reason for mentioning Onyx was not for its prophylactic "maintenance" capabilities but as a tool for dealing with specific issues that already exist. I use it, rarely, but only in response to specific issues.
Disk Warrior while it is great, will not fix a dying hard drive.
Agreed, but I think a dying hard drive is a very different issue from the "maintenance" about which the OP was asking. A dying hard drive is when anybody will need a backup (though I once made it through a dying hard drive case without using my backups or special tools, but that's another story).
Free backup solutions exist.
Software, yes, but the reality of the situation is many people do not consider another $100 for a backup drive to be part of a computer purchase.
Suffice it to say, priority should be placed on backing up before any "maintenance" tools are used.
Uh, again, didn't I say, "Your first priority"???
Since failure of drives can happen at anytime without any warning, due to mechanical issues which no maintenance tool can fix, backing up is still a priority. It should be a part of one's regular routine, and as such is more routine than general maintenance. Maintenance implies a routine practice. Thus backup is maintenance in an indirect way. It is maintenance of your data's integrity.
I think we will have to agree to disagree on the definition of maintenance. For me, maintenance is upkeep of the existing drive, equivalent to changing the oil in my car. I consider a backup like having my second car in case my first car fails, whether it be by an accident or aging. So, I make sure my second car is in good running condition before I start doing any major work on my first car in case something goes wrong during repairs, just the way you might want to back up before you run a tool on a hard drive. I do happen to have a second car; many people don't and then get stuck when the first fails. However, if you
maintain your only car you are
less likely to need that second car (that's why I now own two 28 year old cars 🙂 ). Yes, eventually you will need it, but that will be either due to an accident (= sudden hard drive failure or serious directory crash) or due to the car just wearing out (= hard drive failing after many years of service as they all do). Some people buy new computers before the drives wear out (I think of all the good 250MB drives I have in a box upstairs) so in that case they are simply gambling on their current drive being in good shape mechanically and if they can at least maintain file/directory integrity on the drive they can run
reduced risk of eventually needing that backup.
