I'm moving this thread to the correct section. Please try to post in the correct forum.
Ideally your gecko, if you're talking about a leopard gecko, should have belly heat from an under tank heating pad as opposed to heat from a heat lamp. If the only way you can currently keep the hot side at 92 or so on the floor (not in the air) is by using a heat lamp then you do have to keep it on all the time. If the heat lamp is making the air temp in the 80's or 90's it's too hot for the gecko and you should really consider an under tank heater.