I do something similar.
I have all my gear in one location, mostly packed in small boxes and bags. I use mostly Pelican Micro cases and some boxes from Ultimate Survival. (which I think are made by Otterbox but I have only just found where I can get the Otterboxes here in Australia)
Ive label the contents on all of them using a little brother labeling machine.
I have 4 different size backpacks. I keep my medium large sized pack stocked but open so can quickly zip it and run, but I keep spares and extra stuff organised arround it.
Depending on what I am doing day to day, I move gear backwards and forwards between the 4 packs.
I have forced myself to always leave 1 pack ready to go, for emergencies, and if I take thing out of the boxes for an activity I always put it back in its place before going to bed.
I can walk up and say I need this box, this box, etc and know I have everything I need and I have a couple of boxes spare so I can chop and change as I need.
Its hard to explain exactly what I mean, but It works for me.
One way it does work well is with Batteries. I have 3 different size boxes setup for different situations.
Day to day I use mostly rechargable batteries but the lithiums are there for backup. So I grab the lithium box for the bottom of the bag, then 1 of the other boxes with different amount and sizes ready to go.
Most of my spares and extras are organised into different size fishing tackle type boxes, but the grab and go stuff works better for me in the micro case type boxes.
I figure in an evac type situation, the 4wd backs up the the window next to where its all located and everything gets thrown in the back, (theres a box of clothes ready too) then the rest of my gear in the shed goes in next then lastminute grabs from about the house. I figure about 15+ minutes and Im on the road if pushed.