I've been using my combo (Canon 6d + 24-105 f/4 lens) for about 3 years now, but primarily only on foreign trips so ~15k shots, 10 weeks of intensive usage in total maybe.
I often shoot in dusty locations, whether a windy beach, safari trip, etc.
I don't see any particles of sand on the sensor, and always make sure that when I change lenses, I do so with the camera pointing downwards, and to swap lenses in the minimum amount of time. So hopefully no or not much dust inside the body. However, I worry that dust/sand particles have been blown onto the outside of camera body, and onto the lens, and that by zooming in and out I've been sucking those particles inside the lens.
Is this a valid worry, and should I spend the almost £300 that I've been quoted to have body and lens completely taken apart and thoroughly cleaned?
My worry is that if I don't do it for long enough, the lens will eventually jam, or body stop working. Is it a valid worry?