I think that it is great that you are looking at older dogs, they are sometimes the ones that people often overlook. We got Remi when she was around 7-8, owner said that she was 4. Even now 2 years later, the hubby made the remark that she has lasted longer than we thought that she would. My oldest doberman was 12 years old, the oldest one before him was 9. We were realistic when we took her in, knowing that even if we only had her for a year, that we could make her life as easy as we could and include her in everything that we do. Now it has been 2 years and she is extremely happy and healthy
knockingonwood
. So, you never know, and I think that little dogs usually live longer than the bigger dogs. JMO
Good luck in your seach, and may you find a great companion for many years to come.