1T isn’t dangerous, it just isn’t needed. You only need a 200GB external hard drive. Just plug it in via USB, and copy and paste all the files from your hard drive to the external hard drive. You can do it once a week, but you probably don’t need to unless you’re adding lots of stuff all the time. Once you’ve done the initial backup, you only need to add the files you’ve recently downloaded (ie new music, new picture, new documents, etc) to the hard drive – you don’t need to add every file all over again.