How do you know when it's time? My Mandie is 15. She's had this quick twitching of her eyes. Like a sudden and momentary thing. She's never pooped outside the box but the other day I found some on my floor. Plus her front shoulders have this awful grating feel sometimes when I pick her up. I believe she has a neurological problem that would account for the twitching. This is a crushing blow as I have been with her for 15 years. She's losing her appetite as well.