Which of the following is NOT a condition that may lead to infestation or infection?

The presence of pest control devices does not contribute to conditions that lead to infestation or infection. In fact, these devices are specifically designed to manage and prevent pest issues. They include traps, baits, and other interventions aimed at controlling pest populations or preventing their entry into structures.

On the other hand, excessive moisture can create a conducive environment for pests, such as termites or mold, which can lead to infestations. Faulty grade levels might allow water to pool around structures, promoting dampness and further inviting pests. Earth-wood contacts refer to situations where wood structures touch the soil, which can facilitate pest access, particularly for termites seeking moisture and food sources. Therefore, the correct answer highlights a situation where pest control is actively being employed, in contrast to the other conditions that can lead to pest problems.