There seems to be an idea budding that loft insulation needs to be removed and replaced periodically- what nonsense!

It might need topping up. But in my view it is an unsustainable action to remove and presumably dispose of insulation.

None the less it's a good marketing ploy

Topping up as time goes on, quilt tends not to compact but the need for more is always there

Talking glass fibre here? such horrible stuff.

Are the fibres carcinogenically thin (lung cancer)?

If converting a loft, so insulation moves from loft floor to rafter, what pros and cons of leaving the floor insulation in place? Sound insulation yes but prevents heat rising from below, which can be enough without additional rads upstairs, if highly insulated. In any case, won't the builders want to clear the floor insulation anyway, not have to work itching and breathing the stuff?