Patents work best as a deterrent, much like a fence around your property. It is rarely necessary to actively defend the fence. Even if you do eventually need to mount an active defence it will almost certainly be because your invention has been successful. If it has been sufficiently successful, the cost of a defence will be worthwhile. While the cost of bringing a patent action is high (but falling) the cost of a defence is higher and losing can be ruinous. The usual “relief” awarded to a successful patentee in court is an injunction stopping the defendant from continuing the infringement, and damages. A company which has an established reputation and contractual obligations to supply a product or process which is subsequently found to infringe will no longer be able to meet those obligations and may have to compensate its contractors as well as paying legal costs and damages to the patentee.

Litigation is not the only, or even the preferred method of settling intellectual property disputes. It is almost always the last resort when negotiation, arbitration or mediation has failed.