This research paper from the Housing Finance Policy Center on whether children living with parents saves money and builds wealth. (Spoiler Alert: It Does Not.) It is a fascinating read, however here is the summary:
The sluggish labor market and the increase in housing and education costs following the housing market crisis have encouraged millennials to stay with their parents. These shifts may have long-term consequences, as those who live with their parents delay headship and homeownership. Even though they may save some money by extending their stay with their parents, our results show that such behavior could have a negative long-term impact on their wealth. While many have experienced a decline in their housing wealth during the recession, housing is still one of the most important tools for building long-term wealth. Goodman and Mayer (2018) find that homeownership as an investment has financially outperformed stocks and bonds, even without including benefits from tax subsidy. Choi and coauthors find that those who bought homes between the ages of 25 and 34 have the greatest housing wealth at age 60.1 Those who bought before age 25 receive the biggest housing investment return. In this report, we find no long-term advantage to living with parents. After controlling for other factors, living with parents delays headship and homeownership. Moreover, there is no evidence that those who lived with their parents were able to buy more expensive homes or put more down. While these conclusions should be treated as tentative—considering the study’s limited time frame and because the observations of long-term consequences were drawn from an older group—our results suggest that living with parents has negative long-term economic consequences.