Mine lives on the camera - has done for years, with this actual body, 3 years. OK it comes off to change lens, but one is on all the time, it keeps the dust out. If you only have the one lens, leave it on but turn the thing off. If leaving it for any length of time, like a month or so, I would actually take the battery out too - just enough to disconnect it.
Taking the lens off and putting the body cap on is just giving dust a chance to get in, if you don't, it can't. If you ARE changing lenses, ALWAYS turn the camera off, this reduces the chance of dust being attracted to the sensor if it does have a charge on it.