Its important to back up all of your data pictures, music, and all the rest. You only have one internal drive once it fails all of your data is lost for good. By backing up your computer to an external drive of some sort a full copy of your computer will be saved in case something happens to your main drive internal drive. Drives don’t last forever so be safe and backup.
Before you can set up a backup on your Mac you must first purchase a external drive. To know how big of a drive to get you must first know how the backup works. When you backup your computer for the first time a full and compressed* copy of your main hard drive is made on your external drive. After that every time you backup your computer it will not copy your whole computer again. Instead after your first backup only the changes made to your main drive are backed up to your external drive. For the backups it would be best is you can find a drive that can hold up to six months or more. You backup drive should be about two to three times the size of your internal computer hard drive. For instance I have 512GB computer so I back it up to a 1TB external drive.
Another thing that you must take into account is how you will connect the drive to the computer. If your computer is a 2016 model or newer I would recommend that you find a USB-C or Thunderbolt 3 drives because both of these are newer standards, faster, slimmer, and easier to use. If your computer does not offer USB-C or Thunderbolt 3 then get the next best supported connection type which would be USB-A 3.0 on the side that goes into your computer and on the other side use will be USB-B micro 3.0. Connection forms not to get are older versions of Intel’s Thunderbolt including 1st and 2nd generation and any version that’s under 3.0. Although they are hard to find anymore stay away from both Firewire 400 and 800 because Firewire is a very old standard and in fact the predecessor of Thunderbolt.
Some recommend brands and places to a purchase a new portable drive are:
*Compressed: In computer terms it means a file that is consolidated and shrunk to take up less space.