Most likely you use a USB to backup important documents and files, but why not make the entire process easier? There are several programs that allow you to sync files on your computer with your USB drive. Two of the programs are Allway Sync and Windows Backup Center (comes in Windows).
For Windows Backup Center
Control Panel > System and Security > Back up your computer
Control Panel > System Maintenance > Backup and Restore Center
Then select the USB as the place to backup the files
This way you won't have to manually copy & paste files. Instead, just insert the USB and you're done.
Hope this helps