I’ve fed my dogs OLD ROY for years. They live a full life (14-16 years) and are in good shape.
I got a mixed collie to age 14 on Gravy Train before her back legs gave out. Even the vet who put her down remarked that she had been very well-cared for to make it to that age. And the pitty/shepherd is about to turn 3 and seems to be doing just fine on the same food.