Jennie and her uncle Jack both work for the same large company. Her uncle Jack retired last year and receives a monthly pension that was determined based on his age and years of service. Jennie was looking at her employee manual recently and noticed that her retirement plan is based on regular payments by the company into her pension account and does not promise a fixed sum at retirement, like her uncle is getting.
What are the advantages of Jennie's type of retirement plan, compared with her Uncle Jack's? What are the disadvantages?