Sure, you can macOS, you can download and reinstall all of your apps, but it will take a long time.
Think of all the things you would lose if your hard disk crashed, or if your Mac was damaged or stolen, and you could no longer access your files. Because of this, it is essential to back up your Mac, and to do so regularly. The first law of computing is the one that says you will eventually lose data. You have a lot of valuable data on your Mac, and if you’ve used computers for a long time, you know that it’s not a question of if your hard disk will crash, but rather when it will happen. Software & Apps Intego Personal Backup Compared with Apple’s Time Machine
