You will notice that the area of the c-section scar slowly changes, so much so that you may not notice the difference on a daily basis. You can consider taking pictures to see how the healing process looks for various time periods. In the beginning, right after your c-section, the healing process is fairly rapid and daily changes can be noticed. But after that you may not find the subtle changes as noticeable.
You should always contact your doctor with questions about the c-section scar.
Obstetrics: Normal and Problem Pregnancies. Gabbe, S, Niebyl, J, Simpson, JL. Fifth Edition.