Civil actions, other than those for the recovery of real property, can only be commenced within the periods prescribed in the following sections, after the causes of action shall have accrued; provided, that for the purposes of sections 516.100 to 516.370, the cause of action shall not be deemed to accrue when the wrong is done or the technical breach of contract or duty occurs, but when the damage resulting therefrom is sustained and is capable of ascertainment, and, if more than one item of damage, then the last item, so that all resulting damage may be recovered, and full and complete relief obtained.
§ 516.100, RSMo
RSMo 1939 § 1012