drum spider corroded

12 years is considered very long these days. It's a shame, but anything over seven years now is good going. I'm sure the quality may vary, but as far as I know all drum spiders are made of alloy, mostly aluminium I think. They have always been subject to rotting away as the detergent, as well as a build up of grease and grime, tends to attack it. I've seen many cases where they have cracked or rotted away after just several years. A lot will depend on the water hardness, the type of detergent used, the quantity, and the type of laundry washed i.e. normal soiling or heavily soiled with grease and oil etc. In all honesty 12 years is not anything to complain about. It's highly unlikely that any new machine will last that long unless you invest in something like a Miele.