12 yr old lab

Question
Our 12 year old lab has begun to hide in dark places for hours--closets, empty rooms,etc.  She cannot control her bowel movements (ruined house, rug and autos), has become agressive, and has hip pain, and limps.  I see all of the signs of "the end".  I don't want her in pain, but I can't continue to live like this either.  Any adivce?

Answer
Has she been in for a full work up from the vet, and been cleared that the problems she's having is really an "old age" thing?  Aggression could be from the pain and it might be manageable through medication.  

If there is nothing that the vet can do, you are really the only one that can decide if the time is right for her to go.  If she has lost her quality of life and cannot enjoy herself any longer, it might be time.  But you through knowing her for her whole life will have to judge if you don't see that spark in her eye anymore.

Good luck with your decision.