I have a hummin bird 788 and 550 both of which have switch fire. When turned on you can see your bait on the graph. Fished in a tournament in February of this year. Was having trouble finding any good keepers that day. Seen fish all over the place but could not get them to bite. We were fishing standing timber in 25 ft of water and had the switch fire turned on to see the bait. Fish would come up to the bait and look but not take it. Got back to weigh in and out of 8 boats no one had a single keeper crappie that day. All the technology and no fish for anyone. I normally fish the spots I can see and the ones I know about already and just use the sonar to tell me if there is structure and fish around. I don't depend on it always telling me if the fish are near by as I don't normally fish under the boat. I do use it if I have fished a spot for awhile and have not gotton bit. I will then roll over the area I was casting to and check it out. This tells me if the spot holds fish or not and if it is worth coming back to on a different day or time.