I don't duplicate my core EDC, but I do duplicate some tools at work. I carry a small tool kit in the front pocket of my lunch kit (a Maxpedition Micro), plus a small boo boo kit that fits in an Altoids tin that resides in the other front pocket of my lunch kit. My laptop bag contains a more comprehensive tool kit, with certain redundancies from my lunch kit, and another boo boo kit in an Altoids tin. The reason I due this is I will almost always have either my lunch kit or laptop bag with me, while the other resides in my work van. If I need a tool, I can almost always get by with what I have with me, negating a need to go out to my van for more tools. If I am going to be at a site most/all day and bring in my lunch kit and laptop bag, its only an extra Maxpedition Micro and Altoids tin, so not a lot of extra weight/bulk. It works for me.