My SIL's nanny just quit. My mom actually watches her LO for a good amount of time, so it's not a huge deal, but it's helpful for them to have a part time nanny too. My mom likes to have someone there in the mornings so she can go to the gym, get her errands done, schedule doctors apts, and be able to watch my LO when needed (if I have a dr apt. or bad migraine).
My mom wants someone that she knows and trusts already. This is what she had with our last nanny. I don't think it's realistic that she's going to find someone that way. Did you know your nanny before she became your nanny?