The length of time it takes for pests to be eliminated depends on the pest control method used. For example, if you use pest control products that contain essential oils, it may take a few days for the pests to be eliminated. However, if you use pest control methods like traps or baits, the pests will be killed immediately. If you choose to use poison, it may take a few days for the pest to die. Ultimately, the length of time it takes for pests to be eliminated depends on the pest control method used.