Finding the time to go through and make sure its not relevant (like tax documents) and deduping photos. The ease of capturing things means we have far more to sift through. I agree I would like to just toss, but I have used older documents many times.

There is a bunch of 'duplicate finder' apps for Windows (so I assume for every OS under the sun). It'll take you 10mins the first time, and 1 min every other time.

I run it every few months (or whenever I remember to do so). I don't bother for word/excel/pdf, even if there are some 20MB PDF files, a 5min 1080 shaky vid from a concert you went 5 years ago is a far worthier target for your time.

Documents don’t take up much space. Videos absolutely do though, so you’ll get a pretty good return on investment in going through those.

for me, i just search for the biggest files in my devices, then dedupe the ones with same file-size. Then I take a look on thumbnails of the big files and dedupe in case the thumbnails are the same (^but the file-size is not). Then I sort all the left files on size and look out for general data of same file-size and then decide whether to delete without breaking things or just leave them.

but, I'm thinking putting a NAS in my home and do all the neccessary backup onto that.