Since I took my buddy Fred to the Vet, and had his suffering ended. Fred was 17 years old. In human comparison, That is somewhere between 119 and 113 years old. His pain was no longer hidden.
Ethel and Lucy will both turn twelve later this year. That puts them on the far side of 80 in human years. I am not looking forward to that day when they are obviously suffering, and there is no remedy left.