Joint replacement is not better as early as possible, and it is important to take advantage of the best time for treatment. In general, if a patient does not have joint pain, even if the condition is severe on X-rays, it is not an indication for joint replacement because the primary goal of joint replacement is pain relief. Some conditions need to be treated as soon as possible after diagnosis, however, joint pain is not an indication for early joint replacement. In general, joint disease (excluding tumors) is often treated conservatively first, including physical therapy, medications, joint injections, weight reduction, and treatment of the original disease. Joint replacement is not indicated when pain is mild, conservative treatment is effective, and the patient is young. When conservative treatment is ineffective and the symptoms worsen and cannot be relieved, the impact on daily life is increasing and intolerable, and there are no contraindications to surgery, it is a better time for surgery. The optimal timing of joint replacement cannot be generalized, but must be considered in light of the disease, the severity of symptoms, response to conservative treatment, age, concomitant disease, and the patient’s wishes. For degenerative joint disease, even in the elderly, we recommend that patients begin with conservative treatment, including physical therapy, medications, joint injections, and reduced weight bearing. If the pain is severe and significantly affects normal life, and the patient has a strong desire for joint replacement to improve quality of life, joint replacement can be considered. For patients who do not want to undergo joint replacement surgery because simple conservative treatment is not effective, minimally invasive arthroscopic surgery is a good way to “defend” their joints. Arthroscopic surgery can be combined with other conservative treatments, such as drug injections and physical therapy, to improve the outcome. Of course, if the results of the minimally invasive arthroscopic surgery are not satisfactory, it is not too late to have a joint replacement.