How to deal with clients that ask for new features in the middle of project?


Registered Member
In freelancing, sometimes clients ask to add new feature in the middle of project after having already reached an agreement about tasks and price. So basically adding features for free. If the task is big I usually ask for extra money and time, but for small tasks I do them for free and when the project is finished I realize that I have added numerous tiny features, basically for free. How should I deal with clients who ask for extra features?