No lah, it's not a stupid question, you asked with the right intention, and its a valid question.
Just reading a book from the library "Extreme Digital Photography" by Jonathan Chester. In the book, taking photos in the dessert is a problem, as the sand can get in, so the way is not to change lens, so carry 1 body with wide angle, 1 body with short telephoto, and 1 with long telephotos, .... That way, if you don't change lens, you will minimise the sand going in. Also have to do regular cleaning daily.