It’s always good to have backups because you never know when something is going to fail. This can be said of data as well as hardware.
Working on an important document, save it first to your Dropbox.com folder then save a copy to an external flash however while you update the file make sure you’re updating the dropbox.com file. If something were to go wrong, computer crash, cheap flash drive malfunction or is incompatible (Mac formatted flash drive), you have another copy to work off of.
Also have another printer ready and available for a backup incase something happens when you’re working late at night and need to print important documents first thing in the morning. While attempting to print to my HP Printer, the printer threw an error and told to me to visit HP.com for details about the error. It is 12:30am EST there are more important things than to troubleshoot a printer, therefore I just switched printer to my backup printer a Canon, select print no problem.
Backups whether they be hardware, data/files, or plans are always, always good to have and even though you may not use your backups, there will always be a point in time where you’re extra thankful you had a backup.