I've found the Rocket Air Blower excellent, and for about 5 years it worked every time. However, when I bought a new camera, rather than the normal spots there were doughnut shaped spots on the pictures.
Looking on the internet it appeared that these were spots of liquid,
and no amount of blowing would get rid of them so I had to go to the wet clean option, which I did with Eclipse fluid and Sensor Swabs.
Now be aware that it takes some practice to get good with using the swabs during a wet clean. The first time I did it it made it 10 times worse
as I wasn't careful enough to stop the pad from rubbing the edge of the light box, which dragged a lot of fibres off the pad. Realising my mistake, 2-3 attempts more attempts was enough to clean it completely.
As for how many pads/swabs it will take, it will depend on how stubborn the dust is stuck to the sensor. You should get better with practice, but then hopefully it is something you wouldn't have to do that often.
I do it when I see spots, but always check for spots before a serious shoot, or I go away on holiday.
It is amazing how you sometimes don't see any spots until someone points them out though.
And once you've found a spot(s) you may be surprised to see those spots on images you thought were OK.
A portrait photographer who may normally be at very wide apertures may suddenly see a lot of spots when they go to take some Landscape pics at small apertures, because the camera has been focusing through the spots at very wide apertures.