Pet Insurance is very nessary, Pet Insurance pays the veterinary costs if your pet is ill or has an accident. Some policies also pay out if the pet dies, is lost or stolen.The purpose of pet insurance is to remove the need for the "life or money" decision if a pet guardian is faced with an unexpected and very expensive veterinary bill. Since pets are considered part of the family more and more and veterinary medicine is increasingly using expensive human medical techniques and drugs, pet guardians are facing this emotional decision more frequently than in the past. Policies usually offer to pay 80-90% of the costs minus a $50-100 deductable depending on the company. The owner will usually pay the amount due to the Vet, and then send in the claim form and recieve the reimbursement. In the case of a very high bill, the Vet will usually allow the owner to work out a contingency plan to pay the Vet when the claim is processed.

Pet insurance generally will not pay for preventative veterinary care or elective veterinary care since these costs are known and can be budgetted for in advance. Recently however, some companies in the UK and US are offering routine care coverage as well to help reimburse for all costs related to pet care.
Some insurers cover more than just health issues. It can also cover boarding costs for animals if the owner needs to go into the hospital, and money to help with retrieval of a lost animal, as reward or for posters. With some policies, the owner can receive money if forced to cancel a holiday due to the pet needing urgent treatment or dying.
Some UK policies for dogs also include third party liability insurance. This means, for example, that if the dog causes a car accident that damages a vehicle, the insurance will pay to rectify the damage. Pet Insurance is available in all developed counties and the precise details of the insurance cover will vary from policy to policy.