Reasons
An external hard drive. I recommend a terabyte for peace of mind about not running out of space. I use the Crucial X9 Pro 1TB Portable SSD and it works great.
Worth noting: these are surprisingly expensive (mine was about $120). I believe they're worth it for what they offer you--the ability to step away from your socials without feeling like you're losing important information about yourself and about the way you've spent your time.