- Orthodontic diagnosis and treatment planning must consider the patient's age, as normal dentofacial development differs at each age. Transient malocclusions in children may not require treatment as they often self-correct with growth. - Treating patients early, when growth is active, allows for greater treatment options like guiding growth. Late treatment has limitations as it cannot utilize remaining growth potential. - Younger patients respond better to orthodontic forces due to greater vascularity and cellularity in tissues, making tooth movement faster. Adults have denser bone and narrower apical foramina, slowing movement and increasing risk of damage.