Some chose to let their children pay their own way; some chose to help; some chose to pay.

Depending on ones desire to help or not, the cost of the colleges, plus ones age when your children enter college, it can mean a couple extra years of work to cover the bills left over as a necessary step financially. Not always the case for everyone, but certainly a factor for me as an example.

Unfortunately, prior to age 25 your children have to input their parent's income into any financial aid application regardless of whether or not the parents intend to help with payments, and tragically many big name schools nationwide now charge over $75k per year and somehow expect people earning anything approaching "upper middle class" to pay the entire bill. For me the bills exceeded $700k for 3 kids and that definitely pushed my ability to save for retirement out a few years. College bills can vary widely from family to family, but for sure in some cases it has an impact on the timeline saving for retirement.