With my previous camera I never had problems with dust or other things on the sensor, but because in my new camera the sensor is much closer to the mount, there was suddenly a flake on it that clearly gave a black spot in my images. Since I film semi-professionally and I am paid for it, such a black spot is really not possible. I couldn't find a bellows in all of Enschede, luckily Coolblue could deliver it to me for free on Sundays, so I can clean my sensor just in time.
Tried it right away and it works very well. Used Spot visualizing in Light Room and I can't find a single spot anymore.
Of course, a blower may not be effective in some cases, but with loose dust that did not come off with the automatic cleaning function, I found this blower good enough to clean the sensor quickly and easily. Furthermore, this was the only way that was allowed according to the manual of my camera (sony A7s II) without voiding the warranty.