Backing up macOS is never a bad idea，Because your machine may be damaged、Failure or more serious problem occurs。no matter what happens，Backups can help you get back to work。
How to back up your Mac using Time Machine and iCloud
Back up using iCloud
first，Make sure your Mac backs up files to iCloud。Check steps are as follows：
1.Click the Apple logo in the upper left corner of the menu bar。
2.Select "System Preferences"。
3.Select "Apple ID"。
4.Make sure "iCloud Drive" is selected。
5.Select "Options" on the right side of iCloud Drive。
6.Make sure "Desktop and Documents Folders" is selected。
This ensures that files and folders on your Mac are syncing to iCloud。If you encounter an issue where the Desktop and Documents Folders option cannot be selected or synced，Please log out of iCloud in System Preferences and log in again：System Preferences > Apple ID > Overview > quit。
Back up using Time Machine
To use Time Machine，You need an external drive，Such as USB drive、Another Mac or network-attached storage (NAS) solution。Here are the steps to back up your Mac using Time Machine：
1.Connect an external drive to your Mac。
2.Open the Time Machine app。
3.Select "Select Disk"。
4.Select the external drive from the drop-down menu。
5.Click "Use Disk"。
Make sure "Automatic Backup" is selected on the left side of the window。so，Time Machine creates Mac backups that are always accessible。
Pros and cons of iCloud and Time Machine
iCloud：
•advantage：Real-time file synchronization；Conveniently share files between devices。
•shortcoming：Only 5GB of free storage available，Not suitable for large-scale backup；Upgrading storage costs extra。
Time Machine：
•advantage：Can create a complete snapshot of your Mac；Backup and restore to a certain point in time。
•shortcoming：Backup and recovery processes can be slow；Recovery may fail。
please note，Backing up and syncing files are two different concepts。Time Machine backups are snapshots of your Mac，iCloud is mainly used for file synchronization。
Summarize
To ensure data security，It is recommended to use both Time Machine and iCloud。Time Machine takes care of full backups，iCloud is responsible for file synchronization。This allows you to quickly get back to work if something goes wrong，Also ensure real-time updates of important files。
