Shadowfax is 14 years old and still gets around pretty well for her age. We've tried to do everything we could to keep her healthy for as long as possible. Even with her Cushing's Disease (which we have posted about before 1st post here and 2nd here) we have managed to be pretty lucky with her health.
As she has gotten older we have made some minor changes to our daily activities, we help her up and down the stairs and monitor her more closely when she's outside on the deck when it's raining and slippery. We're also keeping her active. Our two walks a day may be shorter and slower, but we still do them, rain or shine. Allowing her lots of time for sniffing on walks keeps her brain engaged as well as her body physically active.
We have also started making it easier for Shadowfax to get in and out of bed by stacking her dog beds, raising their height. Since we have a lot of dog beds, we put the less popular ones on the bottom and they aren't missed.