Two models of n-unit standby redundant repairable systems are considered. Identifying suitable regeneration points, expressions for the Laplace transform of the following are obtained: availability; reliability; interval reliability; and s-expected number of visits to any state, repair completions, failures, system downs, system recoveries, and s-expected duration of stay in any state. The stationary values of these quantities are also deduced. Two types of cost functions (s-expected net profit rate and s-expected net expenditure rate) are proposed.