The online cloud storage facilities were probably busy all day sucking in new files. But anyone who doesn't trust the cloud will probably find portable drives quite adequate. There's a nifty little utility called RichCopy 220.127.116.11 that makes it very easy to back up Windows files. The user can set the default so that it compares the date and size of the files on the main drive with those on the backup drive, and it replaces only the files that have been changed. It's a real time saver. It's discussed and downloadable here.
So back it on up. It's very easy once a periodic routine is in place.