Dust is more prevalent in some places than in others. If is a fact of life. Many have learned good practices (as you are already seeing), pay attention to those. If it is allowed to accumulate, kids, pets and you will stir it up evry time there is movement.

If your in home/in work environment has high inclination for static electricity buildup (like socks on carpet) it will tend to hold dust on your devices. In home, with A/C, Heating, or whole house ventilation, if that air flow is not filtered, well.... you are pulling in dust, pollen, spores, and the like into your home, onto your stuff (and breathing it as well). We use (high quality) Hepa air filters in the air handler, and change them on a regular schedule, often, as in approx. every 6 weeks in summertime, 2 months or so rest of year. During the winter months, when windows would be open at times, I close/keep closed the camera armoire. All of these things help mitigate.

I did really like Jerry's clean room pic!!! I worked around that type environment at times, hated the gear, but appreciated why!!

I check my gear on a semi-regular basis, and whenever I'm going to use a certain body and lens (or lenses) I check them/blower bulb to lens and caps, front and back, camera body face down bulb blower prior to use. The mention about lens caps (front/rear) is also true - think about where you put them when not attached....I always blow mine off/out prior to putting back on lens, or camera body.

This regimine has served me well, as I rarely have to actually clean a sensor, the bulb blower does the job, along with clean practices. Do thoroughly clean anything I buy used, new stuff, if needed.