Can a Tenant Agree to pay for Improvements?

If a tenant is wanting the carpets in a rental property to be replaced due to the carpets being old, can a landlord enter into an agreement with the tenant for the tenant to pay a portion of the replacement cost?

Under Section 49A Residential Tenancies Act 1986, it is a General Principle that -
(1) Except as provided in section 49B, a tenant has no liability or obligation, and must not be required, to—
(a) meet the cost of making good any destruction of, or damage to, the premises; or
(b) indemnify the landlord against the cost of making good the destruction or damage; or
(c) pay damages related to the destruction or damage; or (d) carry out any works to make good the destruction or damage.

(2) A tenant is not, in any case, liable for fair wear and tear.

If the carpets need to be replaced because of normal wear and tear, the landlord is responsible for covering the entire cost of replacement. It is also important to consider that the Tenancy Tribunal may declare any special clause in the tenancy agreement unenforceable if it imposes obligations on the tenant beyond what is required by the law.