When you think of estate planning, it's common to only think of humans. But, if you want to ensure that your pet maintains a nice life after you pass away, one option is to include them in your will (since legally they are property) and specify what person or place gets them.
You could also then leave a certain amount of money to that person to use in caring for the pet. In that situation, generally, you would want to talk to that person in advance if you could to let them know the money you are bequeathing them is for the pet. You can also look for the best Pet charity organizations that are helpful for pets' lives.
If, however, you are not convinced that you can trust the caretaker of the pet to also properly budget and maintain any money left for the pet, or if you want to avoid any delays in the will going through probate, you can possibly set up a Pet Trust.
A majority of states now allow for Pet Trusts (talk to a lawyer to see about your state). Since 2005, Illinois has provided for the creation of Pet Trusts.
It allows you to form trust and appoint a trustee to manage the money in the trust for pet expenses. This trustee has a fiduciary duty to manage trust money properly.
The trustee can be the same as the caregiver, or you can designate a custodian to physically care for the pet. One way to form a Pet Trust is to create it "interviews" so that it starts while you are living.