After completing a customer software project for a client and after using the program for some time speed issues where discovered.
It is believed that normalizing and optimizing the source code will definately increase the speed of the program.
Is it the responsibility of the coder to go back through the code (remember, the coder has been paid in full already) to improve the performance of the custom software he created for his client "at no additional charge to the client" or should the client pay more money for the coder to optimize the code he already wrote?