Can someone help me on this question, as I am having doubts....

mini-case:

A few weeks ago, your neighbor Mary, a 60-year-old lady, told you that she is seriously thinking about retiring around the end of this year. She has been working part-time as a personal care aidin client's homes with a huge wage cut after she lost her full-time job a few years ago.

A friend of Mary told her that she should stop working because she will get less social security benefit due to her lower wage from the part-time job. Her friend also said the social security benefit is determined based on the average salary of one's working history.

Questions:

1) Would you recommend Mary staying in the work force? Or would you tell her to retire for higher future benefits?

2) How do social security benefit calculation rules have an impact on people's retirement decision?