35mm film cameras did not have big problem with dust because the recording media was wiped clean by the film cassette holder coming out from and being wound into the cassette. But the processed negatives collected dust that needed to be blown off or brushed off before enlarging.
Because the digital camera does not replace the recording media with each shot and the sensor is electronically charged it will gather any dust the enters the camera's mirror box. P&S cameras are pretty well sealed so there is little change of dust getting inside of the camera. dSLR cameras with some lens constructions and the changing of lenses provides an opportunity for dust to get inside the camera and be attracted to the sensor or recording media. Just like the film recording media, the dSLR camera's recording media needs to be cleaned of dust.
More modern dSLRs have a vibrating sensor that can shake dust particles off of the sensor and onto a sticky strip on the bottom of the camera box. But this sensor cleaning will not deal with condensation and dust forming rings or dust and adhering to the sensor. For this only a wet cleaning with lint free swabs and a special cleaning solution will work. The special cleaning solution is designed not harm the filters over the sensor and dry with very little or no streaking. Older dSRLs are cleaned of dust by the use of a Rocket Blower as instructed in the Nikon camera user manual.
Do do not put a cotton swab in a camera's mirror box. Cotton is notoriously full of lint and long fibers. The camera box has a black mat irregular interior designed to reduce or eliminate light reflections. The cotton lint and fibers will adhere to the camera box interior and will cause problems with light reflections or floating into the view finder or onto the sensor.
A well known blogger told of using a vacuum cleaner to remove dust. Maybe tung in check, but another bad idea. The force of the vacuum will bring other material into the camera's mirror box.
Also do not use compressed air cleaners since as the compressed gas expands it also cools, Charles' Law: The Temperature-Volume Law. Also one does not know if water lubricants have been filtered from the compressed air. Then you may have solids within the can that could be propelled with some force onto the sensor and filters.
Oh, by the way, you are a source of dust because your top layer of your skin is constantly shedding and being replaced.