Dogs are such an important part of our lives. Can't imagine life without one.
As for getting older and worrying about our dogs..... arrange for a good friend to take over should things change for the worse. I have been involved a few times with finding a beloved pet a new home. They will adapt and accept their new owners.
I have seen rescues adapt to new environments too. Have one friend that only gets GWPs rescues. Sometgimes there are rough patches but they come around.
