at least once a month i do a tear down, remove and clean all bearings replace whats needed
sometimes you will find some parts are broke or on their way out that you might not notice while the truck is assembled
also a good time to check diff levels
in between tear downs i remove all electronics hose it down scrub with brush then immediately dry with compressed air and finish off with a complete spray of wd-40.
i have my 4wd slash set up so that i only need remove 8 screws and all electronics are out