Your current heirs or beneficiaries of your estate are NOT the best people to provide for the care of your pets after your death.  This is perhaps the most significant of the factors necessitating estate planning for your pet.  That is, although your family and friends may be deserving of your estate,  remember that your pet may not deserve your family and friends.

You live alone.  If you live alone, you should always consider who would come and retrieve your pets if something were to happen to you and when.  This is true regardless of whether long-term estate planning is necessary.

You are advanced in age and/or suffer from a chronic illness.  There is no nice way to say that the shorter your life expectancy is (for whatever reason), the greater the chance that your pet will outlive you and need provisions for its continued care.

Your pets have a relatively long life expectancy.  The longer the life expectancy of your pet is, the greater the chance that your pet will outlive you and need provisions for its continued care.  Conscientious owners of certain parrots and reptiles already know that some pets tend to have very long life expectancies – for example, a large Macaw can live up to 80 years.  Not coincidentally, the pets with the greatest longevity also tend to have the most special needs (as discussed below).  In any case, dog and cat owners should not underestimate the effect that modern advances in veterinary medicine have had on the life expectancies of their pets.  (See How Long Will My Pet Live?)

You have multiple pets.   All other things being equal, if you have multiple pets, there is a greater chance that at least one of those pets will outlive you than if you have only one pet.  Furthermore, even if you have family members who are willing to care for your pets, a single family member may not be willing or able to care for all your pets.  Therefore, if you want your pets to stay together, your may need to plan ahead.

Your pets have special needs.  If your pets have special needs, then those needs should be articulated, and if necessary, financially provided for.  For example, your beloved Great Dane may not fit in your daughter’s one bedroom apartment.  The issue is especially particularly important with regard to exotic animals.  For example, you should not simply assume that your brother will want to, or be able to, provide for your large Cockatoo, a parrot that is particularly prone to loud calls and self-destructive behavior if not given enough hands-on attention.