So your rigs don't share components other than interconnects and SD cards?
That is not my situation...
Yeah, that's right...except I don't share cards and interconnects between bags if possible. I've done that by design, but admittedly it wasn't hard for me to do because I've been doing this for 30 years now and have duplicates upon duplicates of all of the various interconnects and whatnot.
The only shared components I use are my freshest rechargeable batteries and sometimes the battery connector. I literally have a styrofoam cooler filled with cables in my shed. LOL.
The exception to the above it if I'm recording multiple stages at the same time at a festival. Then I have to cross my fingers and hope my older batteries are still working at capacity and don't die too early.
There are two main reasons I can think of that I keep buying the same shit, like interconnects, over and over again 1) I forget what I already have and pick up a new pair of the same thing, or b) I'm already at a festival and find that I left something at home so I have to run to the local music store or Wal-Mart or wherever and buy another set.