>The vast majority (60-80%, Robert L. Glass) of costs for software is also in maintenance, as any of the classic software project management books will tell you

>The vast majority (60-80%, Robert L. Glass) of costs for software is also in maintenance, as any of the classic software project management books will tell you. What's the purpose of stating total costs when discussing monthly costs? Of course maintenance will end up costing more in total if the maintenance period is much longer than the development period. The per month cost is still much lower.