If you are using consumer grade lenses then I would choose one lens for all around use and not take it off to avoid getting dust on the sensor. I don't know how fine the dust is in that particular desert but in Kuwait and Iraq, esp. Kuwait, the dust is fine and pervasive. And if you get caught in a no-sh*t sandstorm, you and your gear are going to get sandblasted. Look out for your laptop too, if you take one.