Performance anti patterns

Question

I am currently working for a client who are petrified of changing lousy un-testable and un-maintainable code because of \"performance reasons\". It is clear t

Answer 1

Changing more than one variable at a time. This drives me absolutely bonkers! How can you determine the impact of a change on a system when more than one thing's been changed?

Related to this, making changes that are not warranted by observations. Why add faster/more CPUs if the process isn't CPU bound?