I'm no expert and I use different machines depending on the conditions. One thing that has helped me was to recognize the stratus of the sand and what is coming up. If it's deep light foil that you digging over and over it might be wise to move on. When working the wet sand I follow the targets lead. If it's deep light crap I move on. If it's heavy targets I'll stick around. Not always the best advice but it works for me.