Limescale is the build up of calcium and magnesium minerals over time leading to a white/yellowish crust on the heating element and other working parts of your washing machine. To tell if your home is prone to limescale check for a furred up heating element in you kettle or spotting on your showerhead. Limescale is prevalent in the Yorkshire Dales and the South East of England including Kent , London and right up to the Midlands.
Whilst there is no doubt that using a product such as Calgon will reduce limescale, the question remains as to whether or not you actually need to, or if this will make any difference to the longevity of your machine.
Which? stated “Using Calgon in every wash, the average person would spend £295 over the course of six to eight years – the time our expert believes it would take before a normal machine in an area with particularly hard water would require attention as a result of limescale build-up. This sum could pay for a brand new washing machine; and you’d expect to get plenty of change if you paid for a service, including removal of limescale.”
It seems there is also evidence to suggest that the ‘furring’ of heating elements as shown in limescale-prevention products advertising is actually caused by using too little washing powder rather than limescale. You can read more about this in this Money Saving Expert thread.
The conclusion would seem to be that whilst products like Calgon do reduce the build-up of limescale this is likely to make little or no difference to the life of your washing machine. Also, using a product like this in a soft water area such as Scotland could actually reduce the effectiveness of your wash by causing excessive soap suds etc.
It seems the most important thing you can do is to use the correct amount of detergent each time you wash as many people use too little.