The German cockroach is the most common species of cockroach found throughout the world. German cockroaches prefer to live in small areas close to food and moisture, so human homes make the perfect habitat. This type of cockroach often hitchhikes indoors via grocery bags, boxes and secondhand appliances, and is commonly found in kitchens and bathrooms. German cockroaches can contaminate food sources and spread bacteria and human pathogens. Moreover, cockroach allergens are know to trigger allergies and exacerbate asthma symptoms, especially in children.
Rodents are like humans in one important way. They like warmth and comfort in the colder months. To find it, they'll look for a hiding place in your home. They often make nests in ceiling cavities, wall cavities and any other warm, dry places they can find. Sometimes it's easy to spot where they have taken up residence. Sometimes you will only become aware of them after they become active at night. Occasionally, you won't even notice them until they do damage to your home.
Unlike humans, a rodent's teeth continue to grow throughout their lifetime. To keep their teeth from growing too much, they gnaw on anything that's available. They gnaw on timber, cladding, electrical wiring and anything else they can find that will file down their teeth. That's actually where the word "rodent" comes from. It was originally a Latin word that meant "to gnaw." It's particularly dangerous when a rodent gnaws through electrical wiring. It may kill the rodent, but the exposed wiring can also cause a house fire.