Removable Disk Backup

Hubby bought me a new laptop and when we got it from store, the guy who took care of us told us that we should also buy a removable disk backup for us to save our important documents here in my laptop and if things happens, if this laptop of mine will get broken and needs to reset all the settings here, i don't have to worry about all the files that i stored here because i have a back up where i store my files. All i have to do is just send my files to this removable disk backup and i am free from any worries about my files. So if you don't have any idea how to store your files and you need to keep some important files, don't wait until your computer gets broken, you should have the removable disk backup.