I rotated 3 evods when I was using clearos.
I kept filling them with the same juice though. I'd rinse them out a few times a week - good solid rinse with scolding hot water, fill it up half way, close it off and shake the crap out if it, empty fill a bit again then blow water through the head. I was .... about it. Probably completely unnecessary. One thought would be to just keep a large class or Tupperware container with water in it and disassemble the tank and chuck it in there to soak until you come back for a full wash.
I don't have tons of tanks. I've only run about three at a time at most. Now my collection of RDAs is getting bigger. I have 5 or so, and use 3 daily, in addition to my kayfun on two different mods.. One for coffee in the morning, two on two different mods for switching flavors through out the day (not exclusively one flavor per dripper, but I try to stick to complementary flavors) and my kayfun for driving.
Everyone does things differently, just find out what works for you!