In Medicine, it is critical "to offer 100% of what is needed and avoid 100% of what is not needed." Unfortunately, this primary issue is challenging, and generally, more than required is offered, and everything that is unnecessary is not avoided. This is a nonsystematic review with a teaching objective that reviews the general issue in primary care and suggests ways to avoid overuse and shortcomings concerning preventive, diagnostic, therapeutic, and rehabilitative interventions. Knowing not to do is science and art that is hardly taught and practiced less. The overuse that harm are an almost daily part of clinical practice in prevention, diagnosis, treatment, and rehabilitation. It is essential to promote "the art and science of not doing".