What it is: Apple recently released the latest version of macOS.
The more you use any computer, the slower it will get. That’s why you need to optimize your files by deleting files and programs you don’t need. However, even deleting a program can leave files behind so the best way to completely optimize your computer is to do a clean install of an operating system.
Such a clean install basically wipes out everything on your hard disk and installs the operating system on the computer as if it were a brand new machine. Of course, before you do a clean install, make sure you copy any critical files. Then do the clean install.
Over time, using any computer will result in files clogging the hard disk, and if you’ve upgraded your operating system several times, that upgrade process alone will likely leave hundreds of useless files scattered across your hard disk. So you have a choice of doing a simple upgrade (and preserving your files) or doing a clean install and optimizing your computer from scratch.
Generally if you want convenience, do an ordinary upgrade. However if you want to optimize your computer, do a clean install. This will dramatically improve your computer’s speed so it will be ready to go another few years of ordinary upgrades.
Just remember that a clean install takes time. First, make sure you copy everything off your computer. (You’ll eventually have to put everything back on your computer again, which will give you time to organize them more efficiently.) Second, do a clean install and wait for an hour or more. Clean installs are time-consuming so don’t do them when you need to use the computer. Finally after a few hours, pray that the clean install actually works properly. Then you’ll be ready for the final step of copying your files back on to your computer again.
Is a clean install worth it? For newer machines, probably not. For older machines, probably yes. Whatever the case, upgrading to the latest version of macOS High Sierra will give you bug fixes that older versions of macOS may by missing. So in general, keep your Macintosh up to date to the latest operating system it can support. Eventually you’ll Macintosh will get too old to support the latest operating system, but until that sad day occurs, keep your old Macintosh alive as long as possible through constant macOS updates. Best of all, macOS updates are free so you have nothing to lose but time.