You really have to investigate before signing up.

Some increase the premium with the pet's age. Some increase the premium if you use it, especially for something which is chronic.

Friend of mine had it for her 2 bichons. One bichon is prone to bladder stones and has now had surgery 4 times for them! The insurance paid their portion of the first bill; and her premium went up 50%. They paid their portion of the 2d surgery and again the premium went up. Friend cancelled the insurance.

Those of us with many pets just sock away funds all the time so we have it available when the need arises.

Like anything else, check reviews online, check Consumer Reports.