I have different "modules" or pouches for different uses I can just put in and out. If it's longer I have a "utility" kit I can add.
I have the minimum, for EDK, then I can add the others as needed. What I have been actually doing lately, is having one of my medium sized bags for out of town trips with non-edk stuff in , then I just add the edk stuff.
I have ready to go, my first aid and meds module, spare batteries, gps, utility module that has stuff like vice grips, foil, safety pins, and other odds and ends that are useful. Wipes, bandana, hygiene module, multitool.
And other stuff. Basically everything I need to be comfortable if I decide or need to spend the night.
If you organize your stuff into short term and long term modules, you can swap them in and out as needed.
It also depends on what you are planning for. Some folks carry a bunch of crap they will probably never use, like fishing supplies and what not, and overlook everyday stuff like a bandana or wipes. If you aren't going into your bob very often, you probably don't have the right kind of stuff in it. Of course it's important to put back in the stuff you use. If you need some ibuprophen, then it should be in your bob, but you need to top it off every now and then.
If you find yourself needing things or wanting something you don't have, a pen, a rubberband, a bungie cord, then you don't have the right stuff.
I tried to think of multi use things. Dental floss can be used for a variety of things. Rubber bands and small bungies are very useful too. Saftey pins, knife or multitool, small vice grips, lighter, a couple esbit tabs, those are all things I've had that came in handy at one time or another.
Your needs may vary from my needs. You might need a space blanket where I may not. I seriously doubt anyone needs fishing supplies but they take up little space, and the line and hooks may be used to fish some keys dropped behind a car seat or something.