The problem is (and it increases with age) - muscles are not your limiting factor long term, connective tissues are. They can be damaged by long term fatigue, or sudden burst of too much strain.
Pushing weights continuously, in higher age, will eventually lead to injury, even if muscles would easily go even further, they are much better at repairing/building up quickly compared to ie tendons or ligaments. Even for young, there is general advice to put 1 week out of ie 10/12 of complete rest, or probably active rest. It is for all those little fractures and sprains in connective tissue to heal a bit. With age, this should be more frequent and/or longer and as usually everything is very individual.
Pushing weights continuously, in higher age, will eventually lead to injury, even if muscles would easily go even further, they are much better at repairing/building up quickly compared to ie tendons or ligaments. Even for young, there is general advice to put 1 week out of ie 10/12 of complete rest, or probably active rest. It is for all those little fractures and sprains in connective tissue to heal a bit. With age, this should be more frequent and/or longer and as usually everything is very individual.