I hear this a lot. I usually retort that I have golf clubs but can't play golf. It's not the clubs and its not the traps. You have to trap all of the moles in your lawn and not just the easy ones. Even systematic trapping may not be and end-all to a mole problem.
Moles always take the path of least resistance when tunneling.
Any neighboring mole will probably recolonize the old tunnels and you will have more trapping to do. Empty tunnels will also be used by dispersing moles in late spring and migrating moles in the fall. I seem to get this a lot especially since some questionable test results from Michigan State University were released and the concoction was allowed to be sold premixed from various manufacturers. I first heard of this old home remedy as a mixture to be prepared in the home workshop by emulsifying medicinal castor oil with a detergent or soap. You were to whip in a blender 3 ounces of castor oil and 3 tablespoons of liquid detergent until frothy.