The financial gurus I listen to on the radio each week tell people all the time they can't afford to pay to send their kids to private college, and that they need to be channeling those funds towards their own retirements or it will come back to haunt them in a big way. (In short, kids can get loans to go to college - nobody loans you money to retire)
It's really quite shocking when they break down the difference in cost today vs 20-40 years ago. One of the hosts points out that she went to a private college in the 60s and she earned HALF the year's costs in her summer job. No kids these days are earning $15K over the summer. However, parents still have the expectation that they "should" be able to send their kids to college as their parents sent them, ignoring the fact that you could be talking a half million dollars for 3 kids for 4 years.
The sad fact is that the cost of college has exploded by many tens of times more than the average income. It's better to fund your retirement (and to be free to give them money THEN towards a home, or loans) than to risk being a burden to your kids later in life because you haven't provided for your own future needs. Their guideline is that you save 20% of your income towards retirement, and AFTER that if you have money left over, you fund the college funds.