I have learned that weight can be an issue with arthritis. From your sig it doesn't look as if Sassy is overweight, but if by any chance she is, losing a few pounds may make the difference. Our RB Nikki was about 8-10 pounds overweight and we noticed she was starting to limp when she was around 7 years old, always after sleeping for a while (the weight pressure on the bones). Losing a few pounds, especially after recommendation from the vet, helped her a lot.