Don't Use DEVONthink as a Junk Drawer
Sometimes, people do indiscriminate dumps (import or index) into DEVONthink or DEVONnote, imagining it to be a Finder or Spotlight replacement. This is really no more truly effective than the junk drawers we all inevitably have at home. And it leads to more false positives in searches and use of far more resources than it needs to.
Searching for a AAA battery in the junk drawer is far harder than it needs to be. Even trying to open that drawer, with screwdrivers and other miscellany snagging against the opening in the cabinet, takes far more energy than it should. If we added some compartments to the drawer (i.e. databases), it will be much easier to open and more efficient to search for that battery.
Of course, how big you make the compartments and organize them is also up to you, but keeping the drawer organized for better and more efficient use will help in the long run.