At approximately what age are medium breed dogs considered 'senior'?

• A. 8-10 years
• B. 6-8 years
• C. 5-7 years
• D. 4-6 years

Answer: (B)

Medium-sized dogs commonly enter the senior stage around six to eight years of age. This timing reflects typical aging changes you’ll see in activity level, joint health, and overall organ aging, which together guide when veterinarians start focusing more on senior preventive care—like more frequent wellness visits, dental care, and potential diet adjustments. There’s natural variation, so some individual dogs may show senior signs a bit earlier or later, but six to eight years is the window many guidelines use for medium breeds. The other ranges tend to correspond to adults still in their prime or to dogs already clearly in the later elderly stage, so they don’t fit as well for when this transition commonly begins.