(a)  In a contract for the sale of goods, payment and delivery are regarded as ‘reciprocal’ duties because the performance of one requires the counter-performance of the other.

(b)  In a contract for the sale of goods, payment and delivery are not regarded as ‘reciprocal’ duties because they can be carried out independently of each other.

(c)   When duties are regarded as ‘reciprocal’ they must usually be carried out at the same time unless otherwise agreed.