It depends on your goals, of course. Let’s say your goal is postponing death. Dr. Lyle J. Dennis says:
“Taken together these findings show that regular slow to average paced jogging 1 to 3 times per week and from 1-2.5 hours had a very potent reduction in mortality compared to not jogging. There may be a U-shaped curve, however, with no statistical benefit to jogging more frequently and at faster paces.”
Read for details of a study on Copenhagen joggers.