When is it Time to Become Dependent???

It's both funny and frustrating watching both of my girls trying to reach higher and higher for the stars to independence. The other day while the bus was pulling up to the house I reached down to give Tayla a kiss and hug and she yelled, "STOP" and pushed me away and then giggled. She didn't want any of the kids on the bus to see her momma kissing or hugging her. As I waved good bye and walked up to the house I almost cried. Another milestone. She is now beginning the, "My Mom is Embarrassing Me" stage. How wonderful.
Nora is going through about a million little stages which all add up to: Independence. She's learning more and more everyday. I may cry right now as I'm typing this...my little girls are growing up too fast!
They're aiming for the stars and trying to catch every little bit of independence that they can collect.
All of this started to make me think about how throughout life we first aim to achieve our independence. Bit by bit we learn to become steady on our own. My question is, "When does it stop?"
My 94 year old grandma, who has been living on her own, in the same 2 story house since her children were born, is now facing this question, "Is it time to become dependent?" She's currently going through rehab due to a fall at her home. Nothing was broken and I'm not even sure she needs rehab. It actually may be a way to stall things out for awhile until the decisions are made. The decision that her children, whom became independent from her, now have to make the decision that I'm sure is not going to be easy. Does my mom need to be dependent?
So here we have a 3 and a 6  year old trying everything possible to gain it while my 94 year old grandma is trying everything possible not to lose it. What do you do? Should you fight until the end?  Should she be able to go back to her 2 story home and live? If her home is taken away from her and she goes to a retirement community, is that giving up or letting go? She does have short term memory loss due to a stroke which is hazardous but wouldn't she be the same a hazard to herself at an Independent Retirement Community? I know that the more independent my children become the stronger it makes them, will this make her weak?
Just some thought going through  my head of how she will handle whatever the outcome will be.
For now, she seems content and that makes me happy!