Older dog

For 6 months or so, Maxine and I have wondered about Cassie's health. She's moving slower, her fur is getting quite grey, and her eyes are developing a haze. All symptoms we saw in our first dog Ally and ones that we worry, seeing in Cassie. Part of the problem is this. Ally died at 14, after having been sick, in various ways, most of her life. She's cost us a bunch of money on doctor bills. Cassie, on the other hand, had been relatively cheap. A yearly checkup, a pronounciation of "her heart is good" by her vet, shots, and we were on our way. But now. She sleeps a lot and doesn't always look up when we walk by, something she always used to do. So now, when she's just a little too still, sleeping, dreaming?, we look at her chest for movement, to see if she's still breathing. We don't like that we have to do it, but we do it.