Monthly breast self-examination is considered the most effective method for the early detection of breast cancer lumps because women who perform regular self-examinations are more likely to notice changes or abnormalities. This enables earlier diagnosis and treatment. Mammograms, while effective, especially for women over 40, are not typically performed as frequently and may not be as useful for younger women with denser breast tissue. Yearly checkups by a physician are important but less frequent compared to monthly self-examinations. Ultrasounds are primarily diagnostic tools used to distinguish between cysts and solid masses rather than a regular screening method.