1 - there’s 2 things to consider here… A) Your files (documents, photos, etc) B) Everything else (the Windows / Linux mac operating system, applications, your screensaver, printer defaults, etc) You only need to backup A. It’s up to you if you want / have space for B But, 1st time, backup everything. Then do item 2 (screw up) big time and do a full restore. Once you’ve done that, you’re set for life