https://web.archive.org/web/20120122115952/http://pileofindexcards.org/blog/2006/10/13/one-pocket-rule/

Noguchi Yukio had a "one pocket rule" which they first described in “「超」整理法 (cho seiri ho)”. The broad idea was to store everything in one place as a means of saving time by not needing to search in multiple repositories for the thing you were hunting for. Despite this advice the Noguchi Filing System didn't take complete advantage of this as one would likely have both a "home" and an "office" system, thus creating two pockets, a problem that exists in an analog world, but which can be mitigated in a digital one.

The one pocket rule can be seen in the IndieWeb principles of owning all your own data on your own website and syndicating out from there. Your single website has the entire store of all your material which makes search much easier. You don't need to recall which platform (Twitter, Facebook, Instagram, et al.) you posted something on, you can save time and find the thing much more quickly by searching one place.

This principle also applies to zettelkasten and commonplace books (well indexed), which allow you to find the data or information you put into them quickly and easily.