There is no "best practice" because everyone's situation is different. Different environment (walls, material, area, # of floors, etc.), different clients, number of clients, bands being used, number and direction of antennas, external interference, etc., etc. Some people base their decisions on nontechnical personal opinions, such as "I want to blast my house with maximum WiFi power" or "I want minimum WiFi power because I'm scared of being irradiated".
I suppose the only thing one could say is that you should use whatever setting works best for you. And you can only find that by experimentation.