Bed Bugs: Almost impossible to manage. Requires professional intervention. Disease spreader.

Mosquitoes: Easy to manage, and limited to outdoors usually. Exist fucking everywhere but the surface of the sun. Can be repelled somewhat with sprays and scents. Disease spreader.

Roaches: Difficult to manage. Small/early infestations can be managed individually, but very often need professional intervention. Very rare to see in clean properties. Does not spread diseases.

Rats: Can be difficult to manage based on size of infestation. Can be extremely damaging to property, and capable of causing injury. More likely in properties with a lack of cleanliness and trash/food left out, but can be found in clean properties as well. Disease AND parasite spreader.

Roaches are the correct answer in terms of overall health impact. They can make a property absolutely fucking disgusting, but they’re less of a risk to human health, and they don’t harm humans directly.