I thought that Gmail’s Archive functionality is useful for a wide range of apps. Why can’t I archive contacts that I don’t plan on contacting, but would like to keep just in case? Or a note in Simplenote (or whatever notes app) that is no longer useful, but which I may want to refer to later? If I write a letter to my bank in Google Docs, why can’t I archive that in case I need to refer to it later? Or SMSs that have information that’s not critical, but which I might want to refer to later?
So, for a while, I thought that archiving  makes sense for all apps that hold your data. But I find that I hardly use it. For example, Google Messenger, the new SMS app on Android, lets me archive conversations, but I find myself never using it, preferring to delete rather than hide unwanted conversations. I then realised that I don’t want the rubbish hanging around. The reason archiving works in mail is that your mail account already has a lot of rubbish in it, so I don’t want more and more places for rubbish to accumulate. That makes me feel a little queasy, just as I’d feel if I’d accumulated physical junk in cupboards and drawers. Better to throw it out and have a clean environment.
 Along with starring, which applies to mails in Gmail, contacts in Google Contacts and Android, docs in Google docs, and many more. Consistency is important — it’s much more user-friendly and useful to have the same concept available in all apps with the same UI (a star) rather than variations with different nuances you need to understand, which is confusing.