There are three basic principles to pest control. The first is to control a pest only when it is causing or will cause more harm than can be reasonably accepted. The second is to use a method of pest control that will reduce the number of pests to an acceptable level (in most cases all pests do not have to be destroyed). Finally, and perhaps most importantly, make sure your pest control method causes minimal harm to everything except the pest. (Ref 1, page 2)
Always think before you act. It can sometimes cost more to control the pest than will be lost because of the damage done by the pest.
All pest control involves one or a combination of these three goals. Prevention is the first goal, which encompasses taking steps so that a pest does not become a problem. Suppression is next, and is key in reducing the numbers of pests and/or the damage they cause to an acceptable level. Finally, there is eradication for destroying the entire pest population at a particular location.
Prevention is of course preferred, but the methods for prevention are limited and it is not always possible to predict which pest will be infesting the area. Suppression is the most common pest control technique, and is more in line with maintaining an appropriate natural balance. Eradication is a last stage measure, and one that is often not really feasible in practical terms. (Ref 1, pages 2-3)
Integrated pest management is combining multiple site-appropriate pest control strategies into a single plan to minimize pests and the associated damage to an acceptable level. Using several different tactics to control a pest problem minimizes the disruption and damage to the living organisms and nonliving surroundings at the treatment site. IPM is considered the "gold standard" in pest control, and is the direction the field is evolving toward in the future. (Ref 2)