One of the best ways to preserve your carpet is to vacuum frequently. Be sure you have a vacuum cleaner that not only pulls up the lint, but is strong enough to get the actual soil out of the carpet
Having doormats in your entry way will significantly decrease the ammount of soil carried in to your home from outside.
Removing your shoes before walking across your carpet is an obvious way to keep unwanted debris off your carpet. However, bare feet on the carpet is just as bad (if not worse). The oil from your feet will cause wear on your carpet.
Moving your furniture around often is a great way to eliminate wear patterns. You do not want the general walkway to remain the same for more than a year (at most).
Having your carpets cleaned professionally is prominent. Depending on your traffic, you may need to have your carpets cleaned anywhere from once to four times a year.
Be weary of what kind of spot cleaners you are using. Some of the products you can purchase at your local store can actually bleach your carpet if not used correctly.
If you clean your carpets yourself using a rug doctor or some kind of rented machine, look into the best kind of solvents to use. Some are mainly a soapy compound. This soap will remain in your carpet and attract new soil to accumulate.