How to stop a program if average change in function value in last 10 iterations is less than 0.001

How can I program to stop execution of my code when average change in value of function let us say 'f' is less than 0.001 in last 10 iterations?

[Jan]

Please provide any details, preferrably the code. The less the readers have to giess, the more likely is a matching answer.

What does " average change in value of function less than 0.001" exactly mean? Do you mean absolute or relative changes?