I've been pretty lucky so far, with two grandparents passing away, mercifully, relatively quickly. My Granddad on my Mom's side of the family was diagnosed with lung cancer right around his 73rd birthday in November 1989. He went in for surgery around Christmas, to see if they could remove the lung, but once they got up in there they saw it had spread to the lymph nodes and other places, so all they could really do was slap him back together and wait for the inevitable. He died in late April, 1990. He went through hell for about 4 months, but I'm just thankful that it didn't drag out for years or decades, even. It was rough enough on Grandmom, and all of us, when he passed away, but I think it would've been much harder to bear if it dragged out. And as far as I know, Grandmom didn't take too much of a financial hit.
On my Dad's side, my grandmother got sick and started to wither away in late 1993, ironically, around her birthday as well. She had just turned 76. I forget what she had, but it was some hereditary disease that had also claimed her mother (they didn't realize it was hereditary until years later though). She passed away in early June, 1994. So I figure she had to suffer about 6-7 months. I remember she was losing her mind as she got worse, too. It was really sad. One of my younger cousins had gotten an earring, and it bothered Grandmom to no end. She kept dwelling on it, repeating about how awful she thought it was, and she just kept repeating to me, asking me not to get one. It's really sad, the things they dwell on when they're fading away.
Anyway, my surviving grandmom is now almost 83, and Granddad turned 92 in October. This may sound like an awful thing to say, but at least the older they get, I guess the chance that when they do die it will be quicker and less painful and drawn out will only increase. And I'm not even thinking about the financial drain it could put on their finances. I just don't want to see them suffer.