Sometimes, adjustments to medication or treatment can help. However, one common suggestion is to look at the 'five good things' your cat enjoys each day. If your cat can no longer experience these simple pleasures, you might consider it's time. Again, only your vet, who knows your cat's health, can make a proper recommendation. It's a very personal, heart-breaking decision, but ultimately, you'll want to consider your beloved pet's comfort and dignity first.