Here’s what’s I did with my son at 22, when he had graduated from university and gotten a job.

I told him I had some good news and some bad news.

The good news was that he could live at home rent-free.

The bad news is that he had to take the amount of money he would otherwise be paying for rent (In Toronto that’s about $1500 a month) and put it into either a savings account or a retirement account.

He did so, and less than two years later he had saved up enough so that (with some help from family members) he could afford a down payment on a small condo.

Now, instead of paying rent, he’s living in a home he owns. At age 25. In Toronto, one of the most expensive markets in North America.

I’m very proud of him.

See also Scott Welch's answer to What’s your most recent DIY project?

Note that this presupposes that the parents are able to afford their own place. If the parents are struggling financially, of course the child should contribute. I was privileged in that I was able to provide this opportunity for my child.