wear and tear.Deterioration caused by ordinary use; the depreciation of property resulting from its reasonable use <the tenant is not liable for normal wear and tear to the leased premises>. — Also termed fair wear and tear; natural wear and tear. [Cases: Landlord and Tenant  55. C.J.S.

Landlord and Tenant § 260.]

“ ‘Fair wear’ is the deterioration caused by the reasonable use of the premises; ‘fair tear’ is the deterioration caused by the ordinary operation of natural forces. A tenant’s repairing covenant commonly exempts the tenant from the obligation to repair damage characterisable as ‘fair wear and tear’ (sometimes called ‘reasonable wear and tear’). In the absence of such an exempting provision, a covenant to repair requires the repairing of damage characterisable as fair wear and tear. Where a covenant to repair exempts the tenant from liability for ‘fair wear and tear’, he is not responsible for deterioration or dilapidation caused by ‘the reasonable use of the house by the tenant and the ordinary operation of natural forces.’ ” Peter Butt, Land Law 256 (2d ed. 1988).
[Blacks Law 8th]