Patients who survive a myocardial infarction (MI) are at increased risk of sudden death due to fatal ventricular arrhythmias. Implantable cardioverter-defibrillators (ICDs) reduce mortality in appropriately selected patients with heart failure and left ventricular dysfunction, regardless of etiology. Post hoc analyses from landmark trials have evaluated the effect of time (both since MI and duration of nonischemic cardiomyopathy) before ICD implantation on the efficacy of ICD therapy. Time remains a clinically important variable in the decision of if and when to implant an ICD. Future trials should focus on invasive and/or noninvasive risk stratification of patients with ischemic and nonischemic cardiomyopathy for better identification of those who would benefit from early ICD implantation, and those in whom a watch and wait approach is appropriate.