In article ,
Mr Fizzion writes:
The question still remains...why would you want to descale a kettle?
Is it building up so much scale on the element that it takes longer to
boil?

That's a very tiny effect.
The element still has to get 3 kW (or whatever it's rated at) out
into the water. If there's a layer of insulating scale around it,
then the element will be running very much hotter, and fail faster
(although nowadays, some other part of the kettle normally fails
before the element, with kettles having become "consumables").
Also tends to make the kettle noisier ("kettling";-).

Even a newly descaled kettle can deposit bits of limescale slime in
your tea, though it does help if you buy one with a mesh filter in the
spout.

IME, mesh filters get blocked with hard water too, and then when
your pour, the water comes out all the wrong places, like round the
side of the lid. Mesh filters need descaling more often than the
element.

--
Andrew Gabriel