You may have heard that in order to keep your Mac running in tip top shape, you need to perform regular maintenance routines on it to clear out caches and other temporary items. These can be useful at times, especially if your system is showing problems with specific applications or services; however, clearing caches, log files, and other so-called “maintenance” routines regularly will often have no effect on the system and may sometimes be entirely unnecessary steps to take.
For the most part, caches on your Mac are used to enhance performance, and regularly stripping them out will at least temporarily degrade performance. In the face of problems that do not resolve themselves, clearing caches may help; however, to do so on a regular schedule will offer no real benefit. If your Mac is regularly slowing down and requiring such maintenance regularly, then you might be better off looking into the specific application or configuration that might be contributing to the problem, instead of simply always resorting to deleting caches and running maintenance scripts.
That being said, there are two maintenance routines that should be run regularly on your Mac, or any computer for that matter. These are Apple’s hardware tests, and a filesystem checking and repairing routine.
The hardware components of your Mac should be fairly robust; however, sometimes faults may develop over time, especially if you have subjected your Mac to harsh conditions or opened and tampered with it. In these instances, while your Mac may continue to function, there may be faults that could lead to hardware or software instability.
To help ensure system components are functioning normally, Apple and component manufacturers embed a number of voltage, current, and temperature sensors for many parts of the system, which can be tested using Apple’s hardware test suite. This suite can be easily launched by restarting your Mac with the D key held down when you hear the boot chimes (or hold the Option-D keys to load the tests from the internet), and then following any on-screen instructions to run the test.
These tests will ensure components and sensors are all working, so if they complete without any errors then you should be good to go (you can look up how to run and interpret these tests here). Otherwise, you should look into having your system checked and possibly repaired at an Apple store or an Apple authorized repair center.
I recommend you run a hardware test on your system every few months.
Hard drive checks
The second component that requires regular checks is your hard drive’s formatting. While the HFS+ (Mac OS Extended) filesystem is fairly robust, even with simple regular use it can incur formatting errors that may result in a slow system. At other times, a hard crash, loss in power, forced-eject of a drive, or manual restart of your system at an improper time may result in damage an attached drive’s formatting.
In addition to the formatting, other aspects of the drive may also get damaged over time. For mechanical drives, bad blocks may begin to appear, or the drive’s controllers and firmware may otherwise stop working properly, resulting in slow performance, crashes, and other issues.
To check for these, at the very least I recommend you run a filesystem formatting verification every month or so using Disk Utility, and then repairing any errors you find when using this routine. In addition, for mechanical drives you can use a third-party drive utility that supports surface integrity scans, to check for bad blocks. Keep in mind that locating and repairing bad blocks can take hours to complete, but this should be a consideration.
While I have outlined these maintenance routines as “required,” I do not intend that others are not useful. Routines for deleting caches and log files, and fixing permissions on your Mac have their places for addressing some problems, but as part of a regular routine to run in the face of no apparent faults or slow-downs, they will likely be unnecessary. On the other hand, ensuring hard drive and hardware health will only give you a regular green light on the state of your Mac.