When the Electrolux 610 and 612 went on sale in the middle part of the 1980's, they were breaking down very quickly, and I know of one woman, a customer of mine, who had bought one of the very first 610 cleaners and had replaced it with a Panasonic before the 610 model had even gone off sale, due to the amount of breakdowns and problems she's had with it. In contrast to this, whilst the clean fan cleaners do not have these problems, they have their own, for instance blocking due to all the ducting which such a cleaner requires to make it what it is, I think above and beyond anything else, what makes a cleaner last longer is how well it was built to start with. The only specific faults which can be attributed to dirty fan cleaners is damage to the fan, the fan housing, and where fitted, the bellows. By the time a vacuum cleaner falls into the hands of a collector or a repair person, the cleaner could have been mended no end of times, and yet on the surface it may seem to be in a condition like it was built at the factory. The longevity of a cleaner will be down to many factors, one of which being how cheaply and easily a cleaner could be put right in the event of a breakdown.
If I am honest, I think we are confusing too many variables from different cleaners across different decades.
