Most people discover a Larder beetle infestation by seeing the adult beetles or finding larvae in their food source.
Another clue that you may have had Larder beetles is finding a clean skeleton of a dead animal.
Seeing a few adult Larder beetles does not necessarily mean there is an infestation, especially if they are found in the spring. The Larder beetles may have wandered inside and are not associated with a food source. However, if you continue to find large numbers of adults or larvae, there is a strong possibility of an infestation.
As long as a food source remains, larder beetles will continue to be a problem.