If something in your rental property is damaged beyond fair wear and tear during your tenancy, your landlord may be entitled to make a deduction from your deposit to cover the cost. But they're not entitled to charge you the full replacement cost if the item was not new when you moved in, and this is where apportionment applies.
Deposit scheme adjudicators use apportionment to calculate a fair deduction, accounting for the age of the item when you moved in, its condition at that point, its expected useful lifespan, and the cost of replacement. The principle is that you should only pay for the portion of the item's useful life that your actions have deprived the landlord of, not for the full cost of upgrading to something new.
For example, if a carpet has an expected lifespan of ten years and it was already five years old when you moved in, you have only benefited from half of its remaining life. If it needs replacing because of damage you caused, the adjudicator would typically hold you liable for around 50% of the replacement cost, not the full amount. The exact calculation depends on the specific circumstances, but the principle is consistent across all three deposit schemes.
This is why your move-in documentation matters so much. If you can show that an item was already aged or worn when you moved in, the apportionment calculation will reduce any deduction. Without that evidence, the landlord's claim for the full replacement cost is much harder to challenge.
.png){kind=small}