It is also important to remember that the tubes must be absolutely free of dirt when they are inserted, i.e. also free of fingerprints.
Such dirt will otherwise burn into the tubes and can result in a very short service life.
The service technician who carried out the first service for us did not take this into account. Fortunately, I was there and cleaned the tubes afterwards.
Yes i am very much aware of this, but brand new out of the papertube should NOT be broken. I get that it can happen. But it has happened more than once.