@valera All bills, receipts, bookmarks, pdf files on topics I'm interested in, research I'm doing, pretty much everything goes into Devonthink. I have it on my phone and my mac. The one on my phone acts as an inbox of sorts. If I see an interesting article in a paper that I may want again, it gets quickly scanned in. I have different databases on the mac version and just sync the inbox between my phone and mac. Then stuff in the inbox gets processed on my mac.
Sometimes I will create a smart group around a topic, for example, I have a current one called "Retrofit" and I have a bunch of stuff in there about insulation, solar panels, heat pumps, grants. Using tags, they all end up grouped together. I'm only using a fraction of its power.