Onyx...he got out while we were unloading some stuff, and disappeared. I didn't realize he was gone until I sat down to dinner and discovered he wasn't sitting beside me, waiting for me to drop something.
We hunted outside with flashlights for a dog that is perfectly camouflaged for moonlit undergrowth (the military should think about this for "evening attire) in addition to being nearly deaf and having poor vision. After about ten minutes I heard Jesse yell, "I found him!" He had walked about one hundred yards down the streeth and was just disappearing into a field. If we had been a few seconds later, we would not have been able to find him.
Yes, he's old, and I may have to make The Decision someday in the near future. But I don't want him to be lost and alone when it's his time.
In the meantime, we try to keep him from escaping outside alone, and take him out for exploration walks every day. He even runs sometimes....he feels pretty good for a dog of 14+!