My guess is that you don't know much about dust mites except they are small, unseen creatures that disgust you. Perhaps someone in your household is allergic to them. Here is some background information on dust mites and how you can work to control them in your house.
Dust mites don't live in your air ducts, although most people tend to focus there when attempting to remove them. They live in soft places, prefer higher humidity and release a protein which causes an allergic reaction for many people. If you don't have any reactions to dust mite proteins then reducing your exposure may not be a priority for you but these basic treatment steps should still be taken to reduce their presence in your home and affect on your life. If you need motivation to do some of these steps you can see pictures of dust mites by doing a google image search. They're gross enough to scare anyone into a rapid cleaning spree.
1. Dust and vacuum your house on a regular basis. The more dirt you have, the more dust mites you have.
2. Use a dehumidifier to reduce the humidity levels in your home as they prefer high humid environments (anything over 70%)
3. Wash your family's bedding in hot water at least twice monthly, preferably weekly.
4. Get machine washable plush toys if you have children, the fabric harbors dust mites
If you have someone allergic to dust mites these are more intense combat steps to take:
1. Do your best to eliminate all cloth surfaces as they tend to harbor these creatures
2. Replace your carpets with wood or laminate flooring
3. Remove fabric covered furniture and switch to wood or plastic pieces
4. Wrap your mattress, pillows and box springs in zippered covers that area dust proof and allergen proof.
You probably won't completely eliminate dust mites, but you can go a long way toward reducing their numbers by maintaining a clean healthy living environment. Your family will thank you for it.