Changes in behavior could be an indication that your dog is experiencing senility or cognitive dysfunction, especially if your dog is over 6-7 years of age. When you notice theses things, like accidents in the house, wandering aimlessly and changes in their eating or drinking habits, it may be time for a trip to the vet. Together, you can assess the situation and see about coming up with a plan for dealing with the issues.
It can be so hard to see your sweet baby dog age and not be the same dog that they once were. Much of the same changes that we see older humans go through, dogs go through as well. Patience and a little extra love can go a long way in helping your dog continue to feel safe and secure in your home.