It is common for old-aged cats to have increased urination which often leads to illnesses that are common to aged felines. Kidney failure, diabetes, and hyperthyroidism are some of the illnesses that can be acquired by ageing cats over time goes.
Another illness that can hinder your cat from using her litter box is Arthritis. She might avoid the litter box due to her worsening arthritis as getting inside and outside her litter might be too painful for her. Thus, she may need a lower box or you may have to place her litter box somewhere that she can access easily.
In addition, your elderly cat may have litterbox problems because there are changes in her eyesight due to glaucoma, a condition where cats get blind or may have decreased vision. Though she has a fair idea of the location of her stuff, once you have rearranged their places, that's the time they find it difficult in locating them.
If you have any concerns about your pet's elimination habits, make an appointment with your local animal hospital Lakewood Ranch, FL.