The visits to the vet would be even more important now as there may be health concerns that would need to be addressed right away instead of allowing them to fester in the hopes that they were "really nothing to be concerned about". His immune system would no longer be as strong as when he was younger and thus he may be more susceptible to infections. His hearing may no longer be as sharp so your older dog may not hear you when you are coming from behind him, when a vehicle gets near or even when a car horn is blown. Try to keep him away from high traffic areas. If there are children in the house, they may have to be told that doggie can no longer stand up to rough play. His bones may also be more brittle so that jumping up and down or even just jumping off a car seat when the car door is opened may spell disaster. You may have to lift him off places where he used to be able to jump down from. His eyes may also be clouding over with cataracts so that his immediate area may have to be cleared of items that he could bump into and topple over such as lamp stands, lightweight pieces of furniture, tall vases that may easily break and the like.
You may have to change his diet into a softer, high protein variety to compensate for any dental problems and his overall lessened dietary requirements. He may also be losing his teeth and may no longer be able to chew on bones the way he used to. If his beddings have remained the same over time, you may consider replacing them with a softer cushion and locating them in a warmer corner, nearer a sunny window or the radiator, especially in wintertime. Your old dog may also have kidney problems that may cause more frequent urination. Be more patient when "accidents" happen. He may also want to drink more water so keep his water dish accessible.
An older dog does not have to be a burden to take care of once his owner starts being aware that he has gotten older and as such would require geriatric care the same way an older person would. With regular visits to the vet, proper nutrition and common sense care, you can still continue having enjoyable times with your dog.