Unless you take a solemn vow to never change lenses on your DSLR, dust and worse will find their way onto your sensor. Much of this is invisible, lost in the shadows and details of an image but some, sometime more than some, will show up repeatedly and need to be removed from the final files. The longer you’re away from home, the worse the dust problem will become.
I’ve just spent three weeks in an unusually dusty Iceland (the Southern part of the country in particular is in the midst of a full on drought) and thanks to the The Visible Dust SensorLoupe ™ I picked up just prior to my departure, along with the same company’s Arctic Butterfly ™ charged brush, I kept my two DSLR sensors pretty much dust free.
So to the fellow tourist who liked my view at Gullfoss so much that he and his extended family had to shuffle over kicking dust into my open camera backpack just as I had pulled off a lens… nice try. I had the Canon 5D factory new that evening. But you and your family are, and will forever remain, clueless.