Development cost versus maintenance cost
I'm trying to explain the ratio of development versus maintenance costs to our sales department, and currently I have mostly my gut feeling that we spend about 60% of the time with maintenance.
We have some persons on the team who tends to sell custom solutions, that we have to build, and if the sales people doesn't understand the total cost of development, then they will not be able to sell for realistic prices.
Another "problem" is that we are expanding our service, and have a need to refactor some of the underlying infrastructure in order to reduce time to market and other measure points.
Do you have any good suggestions on what I should refer to in order to build a solid argument? And what points should I bring up in order to give them a good understanding of the problem?
Maybe there is some great text out there somewhere that I can point to.
Answer
In "Frequently Forgotten Fundamental Facts about Software Engineering" by Robert L. Glass, (an article in IEEE Software May/June 2001), He talks about softwares "60/60" rule, that is that maintenance typically consumes 40 to 80% (60% average) of software costs, and then that enhancement is responsible for roughly 60% of software maintenance costs, while error correction is about 17%.