Everyone wants to stay home and avoid moving to one of those nursing homes or assisted living facilities and my mom and my husband and I feel the same way.
You will know when it is the right time for you or a loved one when the household tasks are becoming overwhelming, you are not eating properly and basically you are feeling pretty isolated depending on other people to help you with most of your routine tasks.
I have seen people who were living on frozen dinners, sitting in the same chair every day and basically doing nothing, but watch television MOVE TO ASSISTED LIVING and become active members of society again.