What's the hot ticket on engine oil?

Advance Auto, Auto zone, Walmart branded diesel 15w-40. Nobody runs their oil for 6000 miles or whatever arbitrary number recommended, not hot rodders IMO. Miserly tightwads maybe. People love to fuss about oil, and refresh the fluids! And end up changing it much sooner than it needs to be. I buy the diesel oils mentioned above as if its gonna be "oil down the drain" more frequently, at least I won't be throwing even more money "under the bridge" :rolleyes: